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| author | Peter Zijlstra <peterz@infradead.org> | 2021-11-10 11:01:10 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-12-11 09:09:47 +0100 |
| commit | d52a7344bdfa9c3442d3f86fb3501d9343726c76 (patch) | |
| tree | 3d077f4a2f9e9bba140ce7139810f233993f3fc3 /arch/x86/mm/extable.c | |
| parent | 4b5305decc8436bfe363d1c1773e8fa1c828b14d (diff) | |
| download | linux-d52a7344bdfa9c3442d3f86fb3501d9343726c76.tar.bz2 | |
x86/msr: Remove .fixup usage
Rework the MSR accessors to remove .fixup usage. Add two new extable
types (to the 4 already existing msr ones) using the new register
infrastructure to record which register should get the error value.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.364084212@infradead.org
Diffstat (limited to 'arch/x86/mm/extable.c')
| -rw-r--r-- | arch/x86/mm/extable.c | 51 |
1 files changed, 28 insertions, 23 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index cef8901b3e6f..717cd35fe41c 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -83,28 +83,29 @@ static bool ex_handler_copy(const struct exception_table_entry *fixup, return ex_handler_fault(fixup, regs, trapnr); } -static bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs) +static bool ex_handler_msr(const struct exception_table_entry *fixup, + struct pt_regs *regs, bool wrmsr, bool safe, int reg) { - if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", + if (!safe && wrmsr && + pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", + (unsigned int)regs->cx, (unsigned int)regs->dx, + (unsigned int)regs->ax, regs->ip, (void *)regs->ip)) + show_stack_regs(regs); + + if (!safe && !wrmsr && + pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", (unsigned int)regs->cx, regs->ip, (void *)regs->ip)) show_stack_regs(regs); - /* Pretend that the read succeeded and returned 0. */ - regs->ax = 0; - regs->dx = 0; - return ex_handler_default(fixup, regs); -} + if (!wrmsr) { + /* Pretend that the read succeeded and returned 0. */ + regs->ax = 0; + regs->dx = 0; + } -static bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup, - struct pt_regs *regs) -{ - if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", - (unsigned int)regs->cx, (unsigned int)regs->dx, - (unsigned int)regs->ax, regs->ip, (void *)regs->ip)) - show_stack_regs(regs); + if (safe) + *pt_regs_nr(regs, reg) = -EIO; - /* Pretend that the write succeeded. */ return ex_handler_default(fixup, regs); } @@ -186,18 +187,22 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, return ex_handler_clear_fs(e, regs); case EX_TYPE_FPU_RESTORE: return ex_handler_fprestore(e, regs); - case EX_TYPE_RDMSR: - return ex_handler_rdmsr_unsafe(e, regs); - case EX_TYPE_WRMSR: - return ex_handler_wrmsr_unsafe(e, regs); case EX_TYPE_BPF: return ex_handler_bpf(e, regs); - case EX_TYPE_RDMSR_IN_MCE: - ex_handler_msr_mce(regs, false); - break; + case EX_TYPE_WRMSR: + return ex_handler_msr(e, regs, true, false, reg); + case EX_TYPE_RDMSR: + return ex_handler_msr(e, regs, false, false, reg); + case EX_TYPE_WRMSR_SAFE: + return ex_handler_msr(e, regs, true, true, reg); + case EX_TYPE_RDMSR_SAFE: + return ex_handler_msr(e, regs, false, true, reg); case EX_TYPE_WRMSR_IN_MCE: ex_handler_msr_mce(regs, true); break; + case EX_TYPE_RDMSR_IN_MCE: + ex_handler_msr_mce(regs, false); + break; case EX_TYPE_POP_ZERO: return ex_handler_pop_zero(e, regs); case EX_TYPE_IMM_REG: |