linux.git/arch/xtensa/kernel/stacktrace.c, branch v6.12.80

xtensa: fix MAKE_PC_FROM_RA second argument

2024-04-03T02:42:35+00:00

Xtensa has two-argument MAKE_PC_FROM_RA macro to convert a0 to an actual
return address because when windowed ABI is used call{,x}{4,8,12}
opcodes stuff encoded window size into the top 2 bits of the register
that becomes a return address in the called function. Second argument of
that macro is supposed to be an address having these 2 topmost bits set
correctly, but the comment suggested that that could be the stack
address. However the stack doesn't have to be in the same 1GByte region
as the code, especially in noMMU XIP configurations.

Fix the comment and use either _text or regs->pc as the second argument
for the MAKE_PC_FROM_RA macro.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov

xtensa: stacktrace: include for prototype

2023-09-20T12:03:20+00:00

Use  to prevent a build warning:

arch/xtensa/kernel/stacktrace.c:263:15: warning: no previous prototype for 'return_address' [-Wmissing-prototypes]
  263 | unsigned long return_address(unsigned level)

Signed-off-by: Randy Dunlap 
Cc: Chris Zankel 
Cc: Max Filippov 
Message-Id: <20230920052139.10570-8-rdunlap@infradead.org>
Signed-off-by: Max Filippov

xtensa: drop ARCH_WANT_FRAME_POINTERS

2023-06-13T02:48:57+00:00

ARCH_WANT_FRAME_POINTERS was enabled in the xtensa Kconfig in the commit
8f371c752154 ("xtensa: enable lockdep support"), but neither windowed
nor call0 xtensa ABI need frame pointers for stack tracing.
Drop ARCH_WANT_FRAME_POINTERS from the xtensa Kconfig.
Drop ftrace_return_address0 definition as the generic implementation is
correct.

Signed-off-by: Max Filippov

arch: xtensa: Remove CONFIG_OPROFILE support

2021-01-29T04:35:51+00:00

The "oprofile" user-space tools don't use the kernel OPROFILE support
any more, and haven't in a long time. User-space has been converted to
the perf interfaces.

Remove the old oprofile's architecture specific support.

Suggested-by: Christoph Hellwig 
Suggested-by: Linus Torvalds 
Signed-off-by: Viresh Kumar 
Acked-by: Robert Richter 
Acked-by: Max Filippov 
Acked-by: William Cohen 
Acked-by: Al Viro 
Acked-by: Thomas Gleixner

xtensa: add support for call0 ABI in userspace

2019-09-01T20:11:57+00:00

Provide a Kconfig choice to select whether only the default ABI, only
call0 ABI or both are supported. The default for XEA2 is windowed, but
it may change for XEA3. Call0 only runs userspace with PS.WOE disabled.
Supporting both windowed and call0 ABIs is tricky, as there's no
indication in the ELF binaries which ABI they use. So it is done by
probing: each process is started with PS.WOE disabled, but the handler
of an illegal instruction exception taken with PS.WOE retries faulting
instruction after enabling PS.WOE. It must happen before any signal is
delivered to the process, otherwise it may be delivered incorrectly.

Signed-off-by: Max Filippov

xtensa: fix return_address

2019-04-04T18:18:55+00:00

return_address returns the address that is one level higher in the call
stack than requested in its argument, because level 0 corresponds to its
caller's return address. Use requested level as the number of stack
frames to skip.

This fixes the address reported by might_sleep and friends.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov

Remove 'type' argument from access_ok() function

2019-01-04T02:57:57+00:00

Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds

xtensa: clean up access to spilled registers locations

2017-05-01T17:34:43+00:00

Define macros SPILL_SLOT* that return a reference to the stack location
of the spill slot for specific register and use them instead of opencoded
address calculations.

Signed-off-by: Max Filippov

Replace with globally

2016-12-24T19:46:01+00:00

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*'
  sed -i -e "s!$PATT!#include !" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro 
Signed-off-by: Linus Torvalds

xtensa: move oprofile stack tracing to stacktrace.c

2015-08-17T04:32:49+00:00

Old oprofile interface will share user stack tracing with new perf
interface. Move oprofile user/kernel stack tracing to stacktrace.c to
make it possible.

Signed-off-by: Max Filippov