From e87f4856a2c4d0dfabe714ad6693e1224d04a99f Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 20 Oct 2021 12:43:51 -0500 Subject: [PATCH] signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT commit 95bf9d646c3c3f95cb0be7e703b371db8da5be68 upstream. When an instruction to save or restore a register from the stack fails in _save_fp_context or _restore_fp_context return with -EFAULT. This change was made to r2300_fpu.S[1] but it looks like it got lost with the introduction of EX2[2]. This is also what the other implementation of _save_fp_context and _restore_fp_context in r4k_fpu.S does, and what is needed for the callers to be able to handle the error. Furthermore calling do_exit(SIGSEGV) from bad_stack is wrong because it does not terminate the entire process it just terminates a single thread. As the changed code was the only caller of arch/mips/kernel/syscall.c:bad_stack remove the problematic and now unused helper function. Cc: Thomas Bogendoerfer Cc: Maciej Rozycki Cc: linux-mips@vger.kernel.org [1] 35938a00ba86 ("MIPS: Fix ISA I FP sigcontext access violation handling") [2] f92722dc4545 ("MIPS: Correct MIPS I FP sigcontext layout") Cc: stable@vger.kernel.org Fixes: f92722dc4545 ("MIPS: Correct MIPS I FP sigcontext layout") Acked-by: Maciej W. Rozycki Acked-by: Thomas Bogendoerfer Link: https://lkml.kernel.org/r/20211020174406.17889-5-ebiederm@xmission.com Signed-off-by: Eric W. Biederman Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/r2300_fpu.S | 4 ++-- arch/mips/kernel/syscall.c | 9 --------- 2 files changed, 2 insertions(+), 11 deletions(-) diff --git a/arch/mips/kernel/r2300_fpu.S b/arch/mips/kernel/r2300_fpu.S index 12e5805..cbf6db9 100644 --- a/arch/mips/kernel/r2300_fpu.S +++ b/arch/mips/kernel/r2300_fpu.S @@ -29,8 +29,8 @@ #define EX2(a,b) \ 9: a,##b; \ .section __ex_table,"a"; \ - PTR 9b,bad_stack; \ - PTR 9b+4,bad_stack; \ + PTR 9b,fault; \ + PTR 9b+4,fault; \ .previous .set mips1 diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c index 2afa3ee..5512cd5 100644 --- a/arch/mips/kernel/syscall.c +++ b/arch/mips/kernel/syscall.c @@ -240,12 +240,3 @@ SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op) { return -ENOSYS; } - -/* - * If we ever come here the user sp is bad. Zap the process right away. - * Due to the bad stack signaling wouldn't work. - */ -asmlinkage void bad_stack(void) -{ - do_exit(SIGSEGV); -} -- 2.7.4