From 56516a42f2f1af01f053eecc4bf3f468d146f2c4 Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Thu, 29 Apr 2021 21:07:33 +0200 Subject: arm: Add compile-time asserts for siginfo_t offsets To help catch ABI breaks at compile-time, add compile-time assertions to verify the siginfo_t layout. This could have caught that we cannot portably add 64-bit integers to siginfo_t on 32-bit architectures like Arm before reaching -next: https://lkml.kernel.org/r/20210422191823.79012-1-elver@google.com Link: https://lkml.kernel.org/r/20210429190734.624918-2-elver@google.com Link: https://lkml.kernel.org/r/20210505141101.11519-2-ebiederm@xmission.com Link: https://lkml.kernel.org/r/87y2a7xx9q.fsf_-_@disp2133 Signed-off-by: Marco Elver Signed-off-by: Eric W. Biederman --- arch/arm/kernel/signal.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'arch/arm/kernel/signal.c') diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a3a38d0a4c85..7ef453e8a96f 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -725,3 +725,40 @@ asmlinkage void do_rseq_syscall(struct pt_regs *regs) rseq_syscall(regs); } #endif + +/* + * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as + * changes likely come with new fields that should be added below. + */ +static_assert(NSIGILL == 11); +static_assert(NSIGFPE == 15); +static_assert(NSIGSEGV == 9); +static_assert(NSIGBUS == 5); +static_assert(NSIGTRAP == 6); +static_assert(NSIGCHLD == 6); +static_assert(NSIGSYS == 2); +static_assert(offsetof(siginfo_t, si_signo) == 0x00); +static_assert(offsetof(siginfo_t, si_errno) == 0x04); +static_assert(offsetof(siginfo_t, si_code) == 0x08); +static_assert(offsetof(siginfo_t, si_pid) == 0x0c); +static_assert(offsetof(siginfo_t, si_uid) == 0x10); +static_assert(offsetof(siginfo_t, si_tid) == 0x0c); +static_assert(offsetof(siginfo_t, si_overrun) == 0x10); +static_assert(offsetof(siginfo_t, si_status) == 0x14); +static_assert(offsetof(siginfo_t, si_utime) == 0x18); +static_assert(offsetof(siginfo_t, si_stime) == 0x1c); +static_assert(offsetof(siginfo_t, si_value) == 0x14); +static_assert(offsetof(siginfo_t, si_int) == 0x14); +static_assert(offsetof(siginfo_t, si_ptr) == 0x14); +static_assert(offsetof(siginfo_t, si_addr) == 0x0c); +static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10); +static_assert(offsetof(siginfo_t, si_lower) == 0x14); +static_assert(offsetof(siginfo_t, si_upper) == 0x18); +static_assert(offsetof(siginfo_t, si_pkey) == 0x14); +static_assert(offsetof(siginfo_t, si_perf_data) == 0x10); +static_assert(offsetof(siginfo_t, si_perf_type) == 0x14); +static_assert(offsetof(siginfo_t, si_band) == 0x0c); +static_assert(offsetof(siginfo_t, si_fd) == 0x10); +static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c); +static_assert(offsetof(siginfo_t, si_syscall) == 0x10); +static_assert(offsetof(siginfo_t, si_arch) == 0x14); -- cgit v1.2.3 From 50ae81305c7a3ee802f0a1988503ce913c79cd6e Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Tue, 4 May 2021 11:25:22 -0500 Subject: signal: Verify the alignment and size of siginfo_t Update the static assertions about siginfo_t to also describe it's alignment and size. While investigating if it was possible to add a 64bit field into siginfo_t[1] it became apparent that the alignment of siginfo_t is as much a part of the ABI as the size of the structure. If the alignment changes siginfo_t when embedded in another structure can move to a different offset. Which is not acceptable from an ABI structure. So document that fact and add static assertions to notify developers if they change change the alignment by accident. [1] https://lkml.kernel.org/r/YJEZdhe6JGFNYlum@elver.google.com Acked-by: Marco Elver v1: https://lkml.kernel.org/r/20210505141101.11519-4-ebiederm@xmission.co Link: https://lkml.kernel.org/r/875yxaxmyl.fsf_-_@disp2133 Signed-off-by: "Eric W. Biederman" --- arch/arm/kernel/signal.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/arm/kernel/signal.c') diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 7ef453e8a96f..f3800c0f428b 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -737,6 +737,8 @@ static_assert(NSIGBUS == 5); static_assert(NSIGTRAP == 6); static_assert(NSIGCHLD == 6); static_assert(NSIGSYS == 2); +static_assert(sizeof(siginfo_t) == 128); +static_assert(__alignof__(siginfo_t) == 4); static_assert(offsetof(siginfo_t, si_signo) == 0x00); static_assert(offsetof(siginfo_t, si_errno) == 0x04); static_assert(offsetof(siginfo_t, si_code) == 0x08); -- cgit v1.2.3 From 12c3dca25d2fa17a101de0d80bf3f238b1cecbae Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Sat, 27 Feb 2021 13:40:09 +0100 Subject: ARM: ep93xx: remove MaverickCrunch support The MaverickCrunch support for ep93xx never made it into glibc and was removed from gcc in its 4.8 release in 2012. It is now one of the last parts of arch/arm/ that fails to build with the clang integrated assembler, which is unlikely to ever want to support it. The two alternatives are to force the use of binutils/gas when building the crunch support, or to remove it entirely. According to Hartley Sweeten: "Martin Guy did a lot of work trying to get the maverick crunch working but I was never able to successfully use it for anything. It "kind" of works but depending on the EP93xx silicon revision there are still a number of hardware bugs that either give imprecise or garbage results. I have no problem with removing the kernel support for the maverick crunch." Unless someone else comes up with a good reason to keep it around, remove it now. This touches mostly the ep93xx platform, but removes a bit of code from ARM common ptrace and signal frame handling as well. If there are remaining users of MaverickCrunch, they can use LTS kernels for at least another five years before kernel support ends. Link: https://lore.kernel.org/linux-arm-kernel/20210802141245.1146772-1-arnd@kernel.org/ Link: https://lore.kernel.org/linux-arm-kernel/20210226164345.3889993-1-arnd@kernel.org/ Link: https://github.com/ClangBuiltLinux/linux/issues/1272 Link: https://gcc.gnu.org/legacy-ml/gcc/2008-03/msg01063.html Cc: "Martin Guy" Signed-off-by: Arnd Bergmann --- arch/arm/kernel/signal.c | 42 ------------------------------------------ 1 file changed, 42 deletions(-) (limited to 'arch/arm/kernel/signal.c') diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a3a38d0a4c85..1162bea3d66f 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -25,40 +25,6 @@ extern const unsigned long sigreturn_codes[17]; static unsigned long signal_return_offset; -#ifdef CONFIG_CRUNCH -static int preserve_crunch_context(struct crunch_sigframe __user *frame) -{ - char kbuf[sizeof(*frame) + 8]; - struct crunch_sigframe *kframe; - - /* the crunch context must be 64 bit aligned */ - kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); - kframe->magic = CRUNCH_MAGIC; - kframe->size = CRUNCH_STORAGE_SIZE; - crunch_task_copy(current_thread_info(), &kframe->storage); - return __copy_to_user(frame, kframe, sizeof(*frame)); -} - -static int restore_crunch_context(char __user **auxp) -{ - struct crunch_sigframe __user *frame = - (struct crunch_sigframe __user *)*auxp; - char kbuf[sizeof(*frame) + 8]; - struct crunch_sigframe *kframe; - - /* the crunch context must be 64 bit aligned */ - kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); - if (__copy_from_user(kframe, frame, sizeof(*frame))) - return -1; - if (kframe->magic != CRUNCH_MAGIC || - kframe->size != CRUNCH_STORAGE_SIZE) - return -1; - *auxp += CRUNCH_STORAGE_SIZE; - crunch_task_restore(current_thread_info(), &kframe->storage); - return 0; -} -#endif - #ifdef CONFIG_IWMMXT static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame) @@ -205,10 +171,6 @@ static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) err |= !valid_user_regs(regs); aux = (char __user *) sf->uc.uc_regspace; -#ifdef CONFIG_CRUNCH - if (err == 0) - err |= restore_crunch_context(&aux); -#endif #ifdef CONFIG_IWMMXT if (err == 0) err |= restore_iwmmxt_context(&aux); @@ -321,10 +283,6 @@ setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; -#ifdef CONFIG_CRUNCH - if (err == 0) - err |= preserve_crunch_context(&aux->crunch); -#endif #ifdef CONFIG_IWMMXT if (err == 0) err |= preserve_iwmmxt_context(&aux->iwmmxt); -- cgit v1.2.3 From 8ac6f5d7f84bf362e67591708bcb9788cdc42c50 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 11 Aug 2021 08:30:26 +0100 Subject: ARM: 9113/1: uaccess: remove set_fs() implementation There are no remaining callers of set_fs(), so just remove it along with all associated code that operates on thread_info->addr_limit. There are still further optimizations that can be done: - In get_user(), the address check could be moved entirely into the out of line code, rather than passing a constant as an argument, - I assume the DACR handling can be simplified as we now only change it during user access when CONFIG_CPU_SW_DOMAIN_PAN is set, but not during set_fs(). Acked-by: Christoph Hellwig Signed-off-by: Arnd Bergmann Signed-off-by: Russell King (Oracle) --- arch/arm/kernel/signal.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'arch/arm/kernel/signal.c') diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index a3a38d0a4c85..3e7ddac086c2 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -711,14 +711,6 @@ struct page *get_signal_page(void) return page; } -/* Defer to generic check */ -asmlinkage void addr_limit_check_failed(void) -{ -#ifdef CONFIG_MMU - addr_limit_user_check(); -#endif -} - #ifdef CONFIG_DEBUG_RSEQ asmlinkage void do_rseq_syscall(struct pt_regs *regs) { -- cgit v1.2.3