linux.git/arch/arm64/kernel/stacktrace.c, branch v5.15.104 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git arm64: Mark start_backtrace() notrace and NOKPROBE_SYMBOL 2022-03-08T18:12:32+00:00 Masami Hiramatsu mhiramat@kernel.org 2022-01-24T08:17:54+00:00 1921d1fd0e603c0b924ffd092d2b5557d9153d2d [ Upstream commit 1e0924bd09916fab795fc2a21ec1d148f24299fd ] Mark the start_backtrace() as notrace and NOKPROBE_SYMBOL because this function is called from ftrace and lockdep to get the caller address via return_address(). The lockdep is used in kprobes, it should also be NOKPROBE_SYMBOL. Fixes: b07f3499661c ("arm64: stacktrace: Move start_backtrace() out of the header") Cc: <stable@vger.kernel.org> # 5.13.x Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/164301227374.1433152.12808232644267107415.stgit@devnote2 Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1e0924bd09916fab795fc2a21ec1d148f24299fd ]

Mark the start_backtrace() as notrace and NOKPROBE_SYMBOL
because this function is called from ftrace and lockdep to
get the caller address via return_address(). The lockdep
is used in kprobes, it should also be NOKPROBE_SYMBOL.

Fixes: b07f3499661c ("arm64: stacktrace: Move start_backtrace() out of the header")
Cc: <stable@vger.kernel.org> # 5.13.x
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/164301227374.1433152.12808232644267107415.stgit@devnote2
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arm64: stacktrace: avoid tracing arch_stack_walk() 2021-08-03T09:39:35+00:00 Mark Rutland mark.rutland@arm.com 2021-08-02T16:48:45+00:00 0c32706dac1b0a72713184246952ab0f54327c21 When the function_graph tracer is in use, arch_stack_walk() may unwind the stack incorrectly, erroneously reporting itself, missing the final entry which is being traced, and reporting all traced entries between these off-by-one from where they should be. When ftrace hooks a function return, the original return address is saved to the fgraph ret_stack, and the return address in the LR (or the function's frame record) is replaced with `return_to_handler`. When arm64's unwinder encounter frames returning to `return_to_handler`, it finds the associated original return address from the fgraph ret stack, assuming the most recent `ret_to_hander` entry on the stack corresponds to the most recent entry in the fgraph ret stack, and so on. When arch_stack_walk() is used to dump the current task's stack, it starts from the caller of arch_stack_walk(). However, arch_stack_walk() can be traced, and so may push an entry on to the fgraph ret stack, leaving the fgraph ret stack offset by one from the expected position. This can be seen when dumping the stack via /proc/self/stack, where enabling the graph tracer results in an unexpected `stack_trace_save_tsk` entry at the start of the trace, and `el0_svc` missing form the end of the trace. This patch fixes this by marking arch_stack_walk() as notrace, as we do for all other functions on the path to ftrace_graph_get_ret_stack(). While a few helper functions are not marked notrace, their calls/returns are balanced, and will have no observable effect when examining the fgraph ret stack. It is possible for an exeption boundary to cause a similar offset if the return address of the interrupted context was in the LR. Fixing those cases will require some more substantial rework, and is left for subsequent patches. Before: | # cat /proc/self/stack | [<0>] proc_pid_stack+0xc4/0x140 | [<0>] proc_single_show+0x6c/0x120 | [<0>] seq_read_iter+0x240/0x4e0 | [<0>] seq_read+0xe8/0x140 | [<0>] vfs_read+0xb8/0x1e4 | [<0>] ksys_read+0x74/0x100 | [<0>] __arm64_sys_read+0x28/0x3c | [<0>] invoke_syscall+0x50/0x120 | [<0>] el0_svc_common.constprop.0+0xc4/0xd4 | [<0>] do_el0_svc+0x30/0x9c | [<0>] el0_svc+0x2c/0x54 | [<0>] el0t_64_sync_handler+0x1a8/0x1b0 | [<0>] el0t_64_sync+0x198/0x19c | # echo function_graph > /sys/kernel/tracing/current_tracer | # cat /proc/self/stack | [<0>] stack_trace_save_tsk+0xa4/0x110 | [<0>] proc_pid_stack+0xc4/0x140 | [<0>] proc_single_show+0x6c/0x120 | [<0>] seq_read_iter+0x240/0x4e0 | [<0>] seq_read+0xe8/0x140 | [<0>] vfs_read+0xb8/0x1e4 | [<0>] ksys_read+0x74/0x100 | [<0>] __arm64_sys_read+0x28/0x3c | [<0>] invoke_syscall+0x50/0x120 | [<0>] el0_svc_common.constprop.0+0xc4/0xd4 | [<0>] do_el0_svc+0x30/0x9c | [<0>] el0t_64_sync_handler+0x1a8/0x1b0 | [<0>] el0t_64_sync+0x198/0x19c After: | # cat /proc/self/stack | [<0>] proc_pid_stack+0xc4/0x140 | [<0>] proc_single_show+0x6c/0x120 | [<0>] seq_read_iter+0x240/0x4e0 | [<0>] seq_read+0xe8/0x140 | [<0>] vfs_read+0xb8/0x1e4 | [<0>] ksys_read+0x74/0x100 | [<0>] __arm64_sys_read+0x28/0x3c | [<0>] invoke_syscall+0x50/0x120 | [<0>] el0_svc_common.constprop.0+0xc4/0xd4 | [<0>] do_el0_svc+0x30/0x9c | [<0>] el0_svc+0x2c/0x54 | [<0>] el0t_64_sync_handler+0x1a8/0x1b0 | [<0>] el0t_64_sync+0x198/0x19c | # echo function_graph > /sys/kernel/tracing/current_tracer | # cat /proc/self/stack | [<0>] proc_pid_stack+0xc4/0x140 | [<0>] proc_single_show+0x6c/0x120 | [<0>] seq_read_iter+0x240/0x4e0 | [<0>] seq_read+0xe8/0x140 | [<0>] vfs_read+0xb8/0x1e4 | [<0>] ksys_read+0x74/0x100 | [<0>] __arm64_sys_read+0x28/0x3c | [<0>] invoke_syscall+0x50/0x120 | [<0>] el0_svc_common.constprop.0+0xc4/0xd4 | [<0>] do_el0_svc+0x30/0x9c | [<0>] el0_svc+0x2c/0x54 | [<0>] el0t_64_sync_handler+0x1a8/0x1b0 | [<0>] el0t_64_sync+0x198/0x19c Cc: <stable@vger.kernel.org> Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Cc: Mark Brown <broonie@kernel.org> Cc: Will Deacon <will@kernel.org> Reviwed-by: Mark Brown <broonie@kernel.org> Link: https://lore.kernel.org/r/20210802164845.45506-3-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> 
When the function_graph tracer is in use, arch_stack_walk() may unwind
the stack incorrectly, erroneously reporting itself, missing the final
entry which is being traced, and reporting all traced entries between
these off-by-one from where they should be.

When ftrace hooks a function return, the original return address is
saved to the fgraph ret_stack, and the return address  in the LR (or the
function's frame record) is replaced with `return_to_handler`.

When arm64's unwinder encounter frames returning to `return_to_handler`,
it finds the associated original return address from the fgraph ret
stack, assuming the most recent `ret_to_hander` entry on the stack
corresponds to the most recent entry in the fgraph ret stack, and so on.

When arch_stack_walk() is used to dump the current task's stack, it
starts from the caller of arch_stack_walk(). However, arch_stack_walk()
can be traced, and so may push an entry on to the fgraph ret stack,
leaving the fgraph ret stack offset by one from the expected position.

This can be seen when dumping the stack via /proc/self/stack, where
enabling the graph tracer results in an unexpected
`stack_trace_save_tsk` entry at the start of the trace, and `el0_svc`
missing form the end of the trace.

This patch fixes this by marking arch_stack_walk() as notrace, as we do
for all other functions on the path to ftrace_graph_get_ret_stack().
While a few helper functions are not marked notrace, their calls/returns
are balanced, and will have no observable effect when examining the
fgraph ret stack.

It is possible for an exeption boundary to cause a similar offset if the
return address of the interrupted context was in the LR. Fixing those
cases will require some more substantial rework, and is left for
subsequent patches.

Before:

| # cat /proc/self/stack
| [<0>] proc_pid_stack+0xc4/0x140
| [<0>] proc_single_show+0x6c/0x120
| [<0>] seq_read_iter+0x240/0x4e0
| [<0>] seq_read+0xe8/0x140
| [<0>] vfs_read+0xb8/0x1e4
| [<0>] ksys_read+0x74/0x100
| [<0>] __arm64_sys_read+0x28/0x3c
| [<0>] invoke_syscall+0x50/0x120
| [<0>] el0_svc_common.constprop.0+0xc4/0xd4
| [<0>] do_el0_svc+0x30/0x9c
| [<0>] el0_svc+0x2c/0x54
| [<0>] el0t_64_sync_handler+0x1a8/0x1b0
| [<0>] el0t_64_sync+0x198/0x19c
| # echo function_graph > /sys/kernel/tracing/current_tracer
| # cat /proc/self/stack
| [<0>] stack_trace_save_tsk+0xa4/0x110
| [<0>] proc_pid_stack+0xc4/0x140
| [<0>] proc_single_show+0x6c/0x120
| [<0>] seq_read_iter+0x240/0x4e0
| [<0>] seq_read+0xe8/0x140
| [<0>] vfs_read+0xb8/0x1e4
| [<0>] ksys_read+0x74/0x100
| [<0>] __arm64_sys_read+0x28/0x3c
| [<0>] invoke_syscall+0x50/0x120
| [<0>] el0_svc_common.constprop.0+0xc4/0xd4
| [<0>] do_el0_svc+0x30/0x9c
| [<0>] el0t_64_sync_handler+0x1a8/0x1b0
| [<0>] el0t_64_sync+0x198/0x19c

After:

| # cat /proc/self/stack
| [<0>] proc_pid_stack+0xc4/0x140
| [<0>] proc_single_show+0x6c/0x120
| [<0>] seq_read_iter+0x240/0x4e0
| [<0>] seq_read+0xe8/0x140
| [<0>] vfs_read+0xb8/0x1e4
| [<0>] ksys_read+0x74/0x100
| [<0>] __arm64_sys_read+0x28/0x3c
| [<0>] invoke_syscall+0x50/0x120
| [<0>] el0_svc_common.constprop.0+0xc4/0xd4
| [<0>] do_el0_svc+0x30/0x9c
| [<0>] el0_svc+0x2c/0x54
| [<0>] el0t_64_sync_handler+0x1a8/0x1b0
| [<0>] el0t_64_sync+0x198/0x19c
| # echo function_graph > /sys/kernel/tracing/current_tracer
| # cat /proc/self/stack
| [<0>] proc_pid_stack+0xc4/0x140
| [<0>] proc_single_show+0x6c/0x120
| [<0>] seq_read_iter+0x240/0x4e0
| [<0>] seq_read+0xe8/0x140
| [<0>] vfs_read+0xb8/0x1e4
| [<0>] ksys_read+0x74/0x100
| [<0>] __arm64_sys_read+0x28/0x3c
| [<0>] invoke_syscall+0x50/0x120
| [<0>] el0_svc_common.constprop.0+0xc4/0xd4
| [<0>] do_el0_svc+0x30/0x9c
| [<0>] el0_svc+0x2c/0x54
| [<0>] el0t_64_sync_handler+0x1a8/0x1b0
| [<0>] el0t_64_sync+0x198/0x19c

Cc: <stable@vger.kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210802164845.45506-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
arm64: stacktrace: use %pSb for backtrace printing 2021-07-08T18:48:22+00:00 Stephen Boyd swboyd@chromium.org 2021-07-08T01:09:24+00:00 f61b8706075a1d04ed27cec369e35cf128c728c3 Let's use the new printk format to print the stacktrace entry when printing a backtrace to the kernel logs. This will include any module's build ID[1] in it so that offline/crash debugging can easily locate the debuginfo for a module via something like debuginfod[2]. Link: https://lkml.kernel.org/r/20210511003845.2429846-7-swboyd@chromium.org Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1] Link: https://sourceware.org/elfutils/Debuginfod.html [2] Signed-off-by: Stephen Boyd <swboyd@chromium.org> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Evan Green <evgreen@chromium.org> Cc: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Young <dyoung@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Sasha Levin <sashal@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Let's use the new printk format to print the stacktrace entry when
printing a backtrace to the kernel logs. This will include any module's
build ID[1] in it so that offline/crash debugging can easily locate the
debuginfo for a module via something like debuginfod[2].

Link: https://lkml.kernel.org/r/20210511003845.2429846-7-swboyd@chromium.org
Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1]
Link: https://sourceware.org/elfutils/Debuginfod.html [2]
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Evan Green <evgreen@chromium.org>
Cc: Hsin-Yi Wang <hsinyi@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Young <dyoung@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arm64: stacktrace: Relax frame record alignment requirement to 8 bytes 2021-05-26T19:01:17+00:00 Peter Collingbourne pcc@google.com 2021-05-26T17:49:26+00:00 33c222aeda14596ca5b9a1a3002858c6c3565ddd The AAPCS places no requirements on the alignment of the frame record. In theory it could be placed anywhere, although it seems sensible to require it to be aligned to 8 bytes. With an upcoming enhancement to tag-based KASAN Clang will begin creating frame records located at an address that is only aligned to 8 bytes. Accommodate such frame records in the stack unwinding code. As pointed out by Mark Rutland, the userspace stack unwinding code has the same problem, so fix it there as well. Signed-off-by: Peter Collingbourne <pcc@google.com> Link: https://linux-review.googlesource.com/id/Ia22c375230e67ca055e9e4bb639383567f7ad268 Acked-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210526174927.2477847-2-pcc@google.com Signed-off-by: Will Deacon <will@kernel.org> 
The AAPCS places no requirements on the alignment of the frame
record. In theory it could be placed anywhere, although it seems
sensible to require it to be aligned to 8 bytes. With an upcoming
enhancement to tag-based KASAN Clang will begin creating frame records
located at an address that is only aligned to 8 bytes. Accommodate
such frame records in the stack unwinding code.

As pointed out by Mark Rutland, the userspace stack unwinding code
has the same problem, so fix it there as well.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ia22c375230e67ca055e9e4bb639383567f7ad268
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210526174927.2477847-2-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
arm64: Change the on_*stack functions to take a size argument 2021-05-26T19:01:17+00:00 Peter Collingbourne pcc@google.com 2021-05-26T17:49:25+00:00 76734d26b54192a31440039459eef2612da63ed4 unwind_frame() was previously implicitly checking that the frame record is in bounds of the stack by enforcing that FP is both aligned to 16 and in bounds of the stack. Once the FP alignment requirement is relaxed to 8 this will not be sufficient because it does not account for the case where FP points to 8 bytes before the end of the stack. Make the check explicit by changing the on_*stack functions to take a size argument and adjusting the callers to pass the appropriate sizes. Signed-off-by: Peter Collingbourne <pcc@google.com> Link: https://linux-review.googlesource.com/id/Ib7a3eb3eea41b0687ffaba045ceb2012d077d8b4 Reviewed-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210526174927.2477847-1-pcc@google.com Signed-off-by: Will Deacon <will@kernel.org> 
unwind_frame() was previously implicitly checking that the frame
record is in bounds of the stack by enforcing that FP is both aligned
to 16 and in bounds of the stack. Once the FP alignment requirement
is relaxed to 8 this will not be sufficient because it does not
account for the case where FP points to 8 bytes before the end of the
stack.

Make the check explicit by changing the on_*stack functions to take a
size argument and adjusting the callers to pass the appropriate sizes.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/Ib7a3eb3eea41b0687ffaba045ceb2012d077d8b4
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210526174927.2477847-1-pcc@google.com
Signed-off-by: Will Deacon <will@kernel.org>
arm64: Implement stack trace termination record 2021-05-25T17:53:29+00:00 Madhavan T. Venkataraman madvenka@linux.microsoft.com 2021-05-10T11:00:26+00:00 7d7b720a4b8049446cffce870b1dd3ffa89d4b40 Reliable stacktracing requires that we identify when a stacktrace is terminated early. We can do this by ensuring all tasks have a final frame record at a known location on their task stack, and checking that this is the final frame record in the chain. We'd like to use task_pt_regs(task)->stackframe as the final frame record, as this is already setup upon exception entry from EL0. For kernel tasks we need to consistently reserve the pt_regs and point x29 at this, which we can do with small changes to __primary_switched, __secondary_switched, and copy_process(). Since the final frame record must be at a specific location, we must create the final frame record in __primary_switched and __secondary_switched rather than leaving this to start_kernel and secondary_start_kernel. Thus, __primary_switched and __secondary_switched will now show up in stacktraces for the idle tasks. Since the final frame record is now identified by its location rather than by its contents, we identify it at the start of unwind_frame(), before we read any values from it. External debuggers may terminate the stack trace when FP == 0. In the pt_regs->stackframe, the PC is 0 as well. So, stack traces taken in the debugger may print an extra record 0x0 at the end. While this is not pretty, this does not do any harm. This is a small price to pay for having reliable stack trace termination in the kernel. That said, gdb does not show the extra record probably because it uses DWARF and not frame pointers for stack traces. Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com> Reviewed-by: Mark Brown <broonie@kernel.org> [Mark: rebase, use ASM_BUG(), update comments, update commit message] Signed-off-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210510110026.18061-1-mark.rutland@arm.com Signed-off-by: Will Deacon <will@kernel.org> 
Reliable stacktracing requires that we identify when a stacktrace is
terminated early. We can do this by ensuring all tasks have a final
frame record at a known location on their task stack, and checking
that this is the final frame record in the chain.

We'd like to use task_pt_regs(task)->stackframe as the final frame
record, as this is already setup upon exception entry from EL0. For
kernel tasks we need to consistently reserve the pt_regs and point x29
at this, which we can do with small changes to __primary_switched,
__secondary_switched, and copy_process().

Since the final frame record must be at a specific location, we must
create the final frame record in __primary_switched and
__secondary_switched rather than leaving this to start_kernel and
secondary_start_kernel. Thus, __primary_switched and
__secondary_switched will now show up in stacktraces for the idle tasks.

Since the final frame record is now identified by its location rather
than by its contents, we identify it at the start of unwind_frame(),
before we read any values from it.

External debuggers may terminate the stack trace when FP == 0. In the
pt_regs->stackframe, the PC is 0 as well. So, stack traces taken in the
debugger may print an extra record 0x0 at the end. While this is not
pretty, this does not do any harm. This is a small price to pay for
having reliable stack trace termination in the kernel. That said, gdb
does not show the extra record probably because it uses DWARF and not
frame pointers for stack traces.

Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
[Mark: rebase, use ASM_BUG(), update comments, update commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210510110026.18061-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 2021-05-07T19:11:05+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-05-07T19:11:05+00:00 51595e3b4943b0079638b2657f603cf5c8ea3a66 Pull more arm64 updates from Catalin Marinas: "A mix of fixes and clean-ups that turned up too late for the first pull request: - Restore terminal stack frame records. Their previous removal caused traces which cross secondary_start_kernel to terminate one entry too late, with a spurious "0" entry. - Fix boot warning with pseudo-NMI due to the way we manipulate the PMR register. - ACPI fixes: avoid corruption of interrupt mappings on watchdog probe failure (GTDT), prevent unregistering of GIC SGIs. - Force SPARSEMEM_VMEMMAP as the only memory model, it saves with having to test all the other combinations. - Documentation fixes and updates: tagged address ABI exceptions on brk/mmap/mremap(), event stream frequency, update booting requirements on the configuration of traps" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: kernel: Update the stale comment arm64: Fix the documented event stream frequency arm64: entry: always set GIC_PRIO_PSR_I_SET during entry arm64: Explicitly document boot requirements for SVE arm64: Explicitly require that FPSIMD instructions do not trap arm64: Relax booting requirements for configuration of traps arm64: cpufeatures: use min and max arm64: stacktrace: restore terminal records arm64/vdso: Discard .note.gnu.property sections in vDSO arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions psci: Remove unneeded semicolon ACPI: irq: Prevent unregistering of GIC SGIs ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure arm64: Show three registers per line arm64: remove HAVE_DEBUG_BUGVERBOSE arm64: alternative: simplify passing alt_region arm64: Force SPARSEMEM_VMEMMAP as the only memory management model arm64: vdso32: drop -no-integrated-as flag 
Pull more arm64 updates from Catalin Marinas:
 "A mix of fixes and clean-ups that turned up too late for the first
  pull request:

   - Restore terminal stack frame records. Their previous removal caused
     traces which cross secondary_start_kernel to terminate one entry
     too late, with a spurious "0" entry.

   - Fix boot warning with pseudo-NMI due to the way we manipulate the
     PMR register.

   - ACPI fixes: avoid corruption of interrupt mappings on watchdog
     probe failure (GTDT), prevent unregistering of GIC SGIs.

   - Force SPARSEMEM_VMEMMAP as the only memory model, it saves with
     having to test all the other combinations.

   - Documentation fixes and updates: tagged address ABI exceptions on
     brk/mmap/mremap(), event stream frequency, update booting
     requirements on the configuration of traps"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: kernel: Update the stale comment
  arm64: Fix the documented event stream frequency
  arm64: entry: always set GIC_PRIO_PSR_I_SET during entry
  arm64: Explicitly document boot requirements for SVE
  arm64: Explicitly require that FPSIMD instructions do not trap
  arm64: Relax booting requirements for configuration of traps
  arm64: cpufeatures: use min and max
  arm64: stacktrace: restore terminal records
  arm64/vdso: Discard .note.gnu.property sections in vDSO
  arm64: doc: Add brk/mmap/mremap() to the Tagged Address ABI Exceptions
  psci: Remove unneeded semicolon
  ACPI: irq: Prevent unregistering of GIC SGIs
  ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure
  arm64: Show three registers per line
  arm64: remove HAVE_DEBUG_BUGVERBOSE
  arm64: alternative: simplify passing alt_region
  arm64: Force SPARSEMEM_VMEMMAP as the only memory management model
  arm64: vdso32: drop -no-integrated-as flag
arm64: stacktrace: restore terminal records 2021-04-30T17:30:45+00:00 Mark Rutland mark.rutland@arm.com 2021-04-29T10:20:04+00:00 8533d5bfad41e74b7dd80d292fd484913cdfb374 We removed the terminal frame records in commit: 6106e1112cc69a36 ("arm64: remove EL0 exception frame record") ... on the assumption that as we no longer used them to find the pt_regs at exception boundaries, they were no longer necessary. However, Leo reports that as an unintended side-effect, this causes traces which cross secondary_start_kernel to terminate one entry too late, with a spurious "0" entry. There are a few ways we could sovle this, but as we're planning to use terminal records for RELIABLE_STACKTRACE, let's revert the logic change for now, keeping the update comments and accounting for the changes in commit: 3c02600144bdb0a1 ("arm64: stacktrace: Report when we reach the end of the stack") This is effectively a partial revert of commit: 6106e1112cc69a36 ("arm64: remove EL0 exception frame record") Signed-off-by: Mark Rutland <mark.rutland@arm.com> Fixes: 6106e1112cc6 ("arm64: remove EL0 exception frame record") Reported-by: Leo Yan <leo.yan@linaro.org> Tested-by: Leo Yan <leo.yan@linaro.org> Cc: Will Deacon <will@kernel.org> Cc: Mark Brown <broonie@kernel.org> Cc: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com> Link: https://lore.kernel.org/r/20210429104813.GA33550@C02TD0UTHF1T.local Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
We removed the terminal frame records in commit:

   6106e1112cc69a36 ("arm64: remove EL0 exception frame record")

... on the assumption that as we no longer used them to find the pt_regs
at exception boundaries, they were no longer necessary.

However, Leo reports that as an unintended side-effect, this causes
traces which cross secondary_start_kernel to terminate one entry too
late, with a spurious "0" entry.

There are a few ways we could sovle this, but as we're planning to use
terminal records for RELIABLE_STACKTRACE, let's revert the logic change
for now, keeping the update comments and accounting for the changes in
commit:

  3c02600144bdb0a1 ("arm64: stacktrace: Report when we reach the end of the stack")

This is effectively a partial revert of commit:

  6106e1112cc69a36 ("arm64: remove EL0 exception frame record")

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 6106e1112cc6 ("arm64: remove EL0 exception frame record")
Reported-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
Link: https://lore.kernel.org/r/20210429104813.GA33550@C02TD0UTHF1T.local
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 2021-04-26T17:25:03+00:00 Linus Torvalds torvalds@linux-foundation.org 2021-04-26T17:25:03+00:00 31a24ae89c92d5533c049046a76c6a2d649efb72 Pull arm64 updates from Catalin Marinas: - MTE asynchronous support for KASan. Previously only synchronous (slower) mode was supported. Asynchronous is faster but does not allow precise identification of the illegal access. - Run kernel mode SIMD with softirqs disabled. This allows using NEON in softirq context for crypto performance improvements. The conditional yield support is modified to take softirqs into account and reduce the latency. - Preparatory patches for Apple M1: handle CPUs that only have the VHE mode available (host kernel running at EL2), add FIQ support. - arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers, new functions for the HiSilicon HHA and L3C PMU, cleanups. - Re-introduce support for execute-only user permissions but only when the EPAN (Enhanced Privileged Access Never) architecture feature is available. - Disable fine-grained traps at boot and improve the documented boot requirements. - Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC). - Add hierarchical eXecute Never permissions for all page tables. - Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs to control which PAC keys are enabled in a particular task. - arm64 kselftests for BTI and some improvements to the MTE tests. - Minor improvements to the compat vdso and sigpage. - Miscellaneous cleanups. * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits) arm64/sve: Add compile time checks for SVE hooks in generic functions arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG. arm64: pac: Optimize kernel entry/exit key installation code paths arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere arm64/sve: Remove redundant system_supports_sve() tests arm64: fpsimd: run kernel mode NEON with softirqs disabled arm64: assembler: introduce wxN aliases for wN registers arm64: assembler: remove conditional NEON yield macros kasan, arm64: tests supports for HW_TAGS async mode arm64: mte: Report async tag faults before suspend arm64: mte: Enable async tag check fault arm64: mte: Conditionally compile mte_enable_kernel_*() arm64: mte: Enable TCO in functions that can read beyond buffer limits kasan: Add report for async mode arm64: mte: Drop arch_enable_tagging() kasan: Add KASAN mode kernel parameter arm64: mte: Add asynchronous mode support arm64: Get rid of CONFIG_ARM64_VHE arm64: Cope with CPUs stuck in VHE mode ... 
Pull arm64 updates from Catalin Marinas:

 - MTE asynchronous support for KASan. Previously only synchronous
   (slower) mode was supported. Asynchronous is faster but does not
   allow precise identification of the illegal access.

 - Run kernel mode SIMD with softirqs disabled. This allows using NEON
   in softirq context for crypto performance improvements. The
   conditional yield support is modified to take softirqs into account
   and reduce the latency.

 - Preparatory patches for Apple M1: handle CPUs that only have the VHE
   mode available (host kernel running at EL2), add FIQ support.

 - arm64 perf updates: support for HiSilicon PA and SLLC PMU drivers,
   new functions for the HiSilicon HHA and L3C PMU, cleanups.

 - Re-introduce support for execute-only user permissions but only when
   the EPAN (Enhanced Privileged Access Never) architecture feature is
   available.

 - Disable fine-grained traps at boot and improve the documented boot
   requirements.

 - Support CONFIG_KASAN_VMALLOC on arm64 (only with KASAN_GENERIC).

 - Add hierarchical eXecute Never permissions for all page tables.

 - Add arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS) allowing user programs
   to control which PAC keys are enabled in a particular task.

 - arm64 kselftests for BTI and some improvements to the MTE tests.

 - Minor improvements to the compat vdso and sigpage.

 - Miscellaneous cleanups.

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (86 commits)
  arm64/sve: Add compile time checks for SVE hooks in generic functions
  arm64/kernel/probes: Use BUG_ON instead of if condition followed by BUG.
  arm64: pac: Optimize kernel entry/exit key installation code paths
  arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
  arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
  arm64/sve: Remove redundant system_supports_sve() tests
  arm64: fpsimd: run kernel mode NEON with softirqs disabled
  arm64: assembler: introduce wxN aliases for wN registers
  arm64: assembler: remove conditional NEON yield macros
  kasan, arm64: tests supports for HW_TAGS async mode
  arm64: mte: Report async tag faults before suspend
  arm64: mte: Enable async tag check fault
  arm64: mte: Conditionally compile mte_enable_kernel_*()
  arm64: mte: Enable TCO in functions that can read beyond buffer limits
  kasan: Add report for async mode
  arm64: mte: Drop arch_enable_tagging()
  kasan: Add KASAN mode kernel parameter
  arm64: mte: Add asynchronous mode support
  arm64: Get rid of CONFIG_ARM64_VHE
  arm64: Cope with CPUs stuck in VHE mode
  ...
arm64: stacktrace: Move start_backtrace() out of the header 2021-03-28T17:09:47+00:00 Mark Brown broonie@kernel.org 2021-03-19T17:40:22+00:00 b07f3499661c61f03478c99ff3fcb2381ddb9e38 Currently start_backtrace() is a static inline function in the header. Since it really shouldn't be sufficiently performance critical that we actually need to have it inlined move it into a C file, this will save anyone else scratching their head about why it is defined in the header. As far as I can see it's only there because it was factored out of the various callers. Signed-off-by: Mark Brown <broonie@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Link: https://lore.kernel.org/r/20210319174022.33051-1-broonie@kernel.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> 
Currently start_backtrace() is a static inline function in the header.
Since it really shouldn't be sufficiently performance critical that we
actually need to have it inlined move it into a C file, this will save
anyone else scratching their head about why it is defined in the header.
As far as I can see it's only there because it was factored out of the
various callers.

Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210319174022.33051-1-broonie@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>