diff options
| author |   Nadav Amit <namit@vmware.com> | 2019-04-25 17:11:28 -0700 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-04-30 12:37:53 +0200 |
| commit | 86a22057127d1c0462a18901421bf1ff89491392 (patch) | |
| tree | a5ebc1194034b45a449a67140ec5a3520a190a6c | |
| parent | x86/alternatives: Use temporary mm for text poking (diff) | |
| download | linux-dev-86a22057127d1c0462a18901421bf1ff89491392.tar.xz linux-dev-86a22057127d1c0462a18901421bf1ff89491392.zip | |
x86/kgdb: Avoid redundant comparison of patched code
text_poke() already ensures that the written value is the correct one
and fails if that is not the case. There is no need for an additional
comparison. Remove it.
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-9-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/kgdb.c | 14 |
1 files changed, 1 insertions, 13 deletions
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 2b203ee5b879..13b13311b792 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -747,7 +747,6 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) { int err; - char opc[BREAK_INSTR_SIZE]; bpt->type = BP_BREAKPOINT; err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr, @@ -766,11 +765,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) return -EBUSY; text_poke_kgdb((void *)bpt->bpt_addr, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE); - err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); - if (err) - return err; - if (memcmp(opc, arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE)) - return -EINVAL; bpt->type = BP_POKE_BREAKPOINT; return err; @@ -778,9 +772,6 @@ int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt) int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) { - int err; - char opc[BREAK_INSTR_SIZE]; - if (bpt->type != BP_POKE_BREAKPOINT) goto knl_write; /* @@ -791,10 +782,7 @@ int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt) goto knl_write; text_poke_kgdb((void *)bpt->bpt_addr, bpt->saved_instr, BREAK_INSTR_SIZE); - err = probe_kernel_read(opc, (char *)bpt->bpt_addr, BREAK_INSTR_SIZE); - if (err || memcmp(opc, bpt->saved_instr, BREAK_INSTR_SIZE)) - goto knl_write; - return err; + return 0; knl_write: return probe_kernel_write((char *)bpt->bpt_addr, |