From 1e688dd2a3d6759d416616ff07afc4bb836c4213 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 13 Apr 2021 16:38:10 +0000 Subject: powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto Using asm goto in __WARN_FLAGS() and WARN_ON() allows more flexibility to GCC. For that add an entry to the exception table so that program_check_exception() knowns where to resume execution after a WARNING. Here are two exemples. The first one is done on PPC32 (which benefits from the previous patch), the second is on PPC64. unsigned long test(struct pt_regs *regs) { int ret; WARN_ON(regs->msr & MSR_PR); return regs->gpr[3]; } unsigned long test9w(unsigned long a, unsigned long b) { if (WARN_ON(!b)) return 0; return a / b; } Before the patch: 000003a8 : 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 3c0: 80 63 00 0c lwz r3,12(r3) 3c4: 4e 80 00 20 blr 0000000000000bf0 <.test9w>: bf0: 7c 89 00 74 cntlzd r9,r4 bf4: 79 29 d1 82 rldicl r9,r9,58,6 bf8: 0b 09 00 00 tdnei r9,0 bfc: 2c 24 00 00 cmpdi r4,0 c00: 41 82 00 0c beq c0c <.test9w+0x1c> c04: 7c 63 23 92 divdu r3,r3,r4 c08: 4e 80 00 20 blr c0c: 38 60 00 00 li r3,0 c10: 4e 80 00 20 blr After the patch: 000003a8 : 3a8: 81 23 00 84 lwz r9,132(r3) 3ac: 71 29 40 00 andi. r9,r9,16384 3b0: 40 82 00 0c bne 3bc 3b4: 80 63 00 0c lwz r3,12(r3) 3b8: 4e 80 00 20 blr 3bc: 0f e0 00 00 twui r0,0 0000000000000c50 <.test9w>: c50: 7c 89 00 74 cntlzd r9,r4 c54: 79 29 d1 82 rldicl r9,r9,58,6 c58: 0b 09 00 00 tdnei r9,0 c5c: 7c 63 23 92 divdu r3,r3,r4 c60: 4e 80 00 20 blr c70: 38 60 00 00 li r3,0 c74: 4e 80 00 20 blr In the first exemple, we see GCC doesn't need to duplicate what happens after the trap. In the second exemple, we see that GCC doesn't need to emit a test and a branch in the likely path in addition to the trap. We've got some WARN_ON() in .softirqentry.text section so it needs to be added in the OTHER_TEXT_SECTIONS in modpost.c Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/389962b1b702e3c78d169e59bcfac56282889173.1618331882.git.christophe.leroy@csgroup.eu --- scripts/mod/modpost.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'scripts/mod') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 270a7df898e2..1209e1786af7 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -931,7 +931,7 @@ static void check_section(const char *modname, struct elf_info *elf, ".kprobes.text", ".cpuidle.text", ".noinstr.text" #define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ ".fixup", ".entry.text", ".exception.text", ".text.*", \ - ".coldtext" + ".coldtext", ".softirqentry.text" #define INIT_SECTIONS ".init.*" #define MEM_INIT_SECTIONS ".meminit.*" -- cgit v1.2.3 From cc6711b0bf36de068b10490198d05ac168377989 Mon Sep 17 00:00:00 2001 From: Max Gurtovoy Date: Thu, 26 Aug 2021 13:39:09 +0300 Subject: PCI / VFIO: Add 'override_only' support for VFIO PCI sub system Expose an 'override_only' helper macro (i.e. PCI_DRIVER_OVERRIDE_DEVICE_VFIO) for VFIO PCI sub system and add the required code to prefix its matching entries with "vfio_" in modules.alias file. It allows VFIO device drivers to include match entries in the modules.alias file produced by kbuild that are not used for normal driver autoprobing and module autoloading. Drivers using these match entries can be connected to the PCI device manually, by userspace, using the existing driver_override sysfs. For example the resulting modules.alias may have: alias pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_core alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci In this example mlx5_core and mlx5_vfio_pci match to the same PCI device. The kernel will autoload and autobind to mlx5_core but the kernel and udev mechanisms will ignore mlx5_vfio_pci. When userspace wants to change a device to the VFIO subsystem it can implement a generic algorithm: 1) Identify the sysfs path to the device: /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 2) Get the modalias string from the kernel: $ cat /sys/bus/pci/devices/0000:01:00.0/modalias pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00 3) Prefix it with vfio_: vfio_pci:v000015B3d00001021sv000015B3sd00000001bc02sc00i00 4) Search modules.alias for the above string and select the entry that has the fewest *'s: alias vfio_pci:v000015B3d00001021sv*sd*bc*sc*i* mlx5_vfio_pci 5) modprobe the matched module name: $ modprobe mlx5_vfio_pci 6) cat the matched module name to driver_override: echo mlx5_vfio_pci > /sys/bus/pci/devices/0000:01:00.0/driver_override 7) unbind device from original module echo 0000:01:00.0 > /sys/bus/pci/devices/0000:01:00.0/driver/unbind 8) probe PCI drivers (or explicitly bind to mlx5_vfio_pci) echo 0000:01:00.0 > /sys/bus/pci/drivers_probe The algorithm is independent of bus type. In future the other buses with VFIO device drivers, like platform and ACPI, can use this algorithm as well. This patch is the infrastructure to provide the information in the modules.alias to userspace. Convert the only VFIO pci_driver which results in one new line in the modules.alias: alias vfio_pci:v*d*sv*sd*bc*sc*i* vfio_pci Later series introduce additional HW specific VFIO PCI drivers, such as mlx5_vfio_pci. Signed-off-by: Max Gurtovoy Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas # for pci.h Signed-off-by: Yishai Hadas Link: https://lore.kernel.org/r/20210826103912.128972-11-yishaih@nvidia.com Signed-off-by: Alex Williamson --- scripts/mod/devicetable-offsets.c | 1 + scripts/mod/file2alias.c | 17 +++++++++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-) (limited to 'scripts/mod') diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c index 9bb6c7edccc4..cc3625617a0e 100644 --- a/scripts/mod/devicetable-offsets.c +++ b/scripts/mod/devicetable-offsets.c @@ -42,6 +42,7 @@ int main(void) DEVID_FIELD(pci_device_id, subdevice); DEVID_FIELD(pci_device_id, class); DEVID_FIELD(pci_device_id, class_mask); + DEVID_FIELD(pci_device_id, override_only); DEVID(ccw_device_id); DEVID_FIELD(ccw_device_id, match_flags); diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 7c97fa8e36bc..49aba862073e 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -426,7 +426,7 @@ static int do_ieee1394_entry(const char *filename, return 1; } -/* Looks like: pci:vNdNsvNsdNbcNscNiN. */ +/* Looks like: pci:vNdNsvNsdNbcNscNiN or _pci:vNdNsvNsdNbcNscNiN. */ static int do_pci_entry(const char *filename, void *symval, char *alias) { @@ -440,8 +440,21 @@ static int do_pci_entry(const char *filename, DEF_FIELD(symval, pci_device_id, subdevice); DEF_FIELD(symval, pci_device_id, class); DEF_FIELD(symval, pci_device_id, class_mask); + DEF_FIELD(symval, pci_device_id, override_only); + + switch (override_only) { + case 0: + strcpy(alias, "pci:"); + break; + case PCI_ID_F_VFIO_DRIVER_OVERRIDE: + strcpy(alias, "vfio_pci:"); + break; + default: + warn("Unknown PCI driver_override alias %08X\n", + override_only); + return 0; + } - strcpy(alias, "pci:"); ADD(alias, "v", vendor != PCI_ANY_ID, vendor); ADD(alias, "d", device != PCI_ANY_ID, device); ADD(alias, "sv", subvendor != PCI_ANY_ID, subvendor); -- cgit v1.2.3 From e54dd93a08228b9942d708b133ad3715d92712b0 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 28 Aug 2021 18:50:59 +0900 Subject: modpost: get the *.mod file path more simply get_src_version() strips 'o' or 'lto.o' from the end of the object file path (so, postfixlen is 1 or 5), then adds 'mod'. If you look at the code closely, mod->name already holds the base path with the extension stripped. Most of the code changes made by commit 7ac204b545f2 ("modpost: lto: strip .lto from module names") was actually unneeded. sumversion.c does not need strends(), so it can get back local in modpost.c again. Signed-off-by: Masahiro Yamada --- scripts/mod/modpost.c | 11 ++++++++++- scripts/mod/modpost.h | 9 --------- scripts/mod/sumversion.c | 7 +------ 3 files changed, 11 insertions(+), 16 deletions(-) (limited to 'scripts/mod') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 270a7df898e2..a26139aa57fd 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include "modpost.h" #include "../../include/linux/license.h" @@ -89,6 +90,14 @@ modpost_log(enum loglevel loglevel, const char *fmt, ...) error_occurred = true; } +static inline bool strends(const char *str, const char *postfix) +{ + if (strlen(str) < strlen(postfix)) + return false; + + return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; +} + void *do_nofail(void *ptr, const char *expr) { if (!ptr) @@ -2060,7 +2069,7 @@ static void read_symbols(const char *modname) if (!mod->is_vmlinux) { version = get_modinfo(&info, "version"); if (version || all_versions) - get_src_version(modname, mod->srcversion, + get_src_version(mod->name, mod->srcversion, sizeof(mod->srcversion) - 1); } diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index c1a895c0d682..0c47ff95c0e2 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -2,7 +2,6 @@ #include #include #include -#include #include #include #include @@ -178,14 +177,6 @@ static inline unsigned int get_secindex(const struct elf_info *info, return info->symtab_shndx_start[sym - info->symtab_start]; } -static inline bool strends(const char *str, const char *postfix) -{ - if (strlen(str) < strlen(postfix)) - return false; - - return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; -} - /* file2alias.c */ extern unsigned int cross_build; void handle_moddevtable(struct module *mod, struct elf_info *info, diff --git a/scripts/mod/sumversion.c b/scripts/mod/sumversion.c index 760e6baa7eda..905c0ec291e1 100644 --- a/scripts/mod/sumversion.c +++ b/scripts/mod/sumversion.c @@ -391,14 +391,9 @@ void get_src_version(const char *modname, char sum[], unsigned sumlen) struct md4_ctx md; char *fname; char filelist[PATH_MAX + 1]; - int postfix_len = 1; - - if (strends(modname, ".lto.o")) - postfix_len = 5; /* objects for a module are listed in the first line of *.mod file. */ - snprintf(filelist, sizeof(filelist), "%.*smod", - (int)strlen(modname) - postfix_len, modname); + snprintf(filelist, sizeof(filelist), "%s.mod", modname); buf = read_text_file(filelist); -- cgit v1.2.3