x86/mce: Provide method to find out the type of an exception handler

Avoid a proliferation of ex_has_*_handler() functions by having just
one function that returns the type of the handler (if any).

Drop the __visible attribute for this function. It is not called
from assembler so the attribute is not necessary.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201006210910.21062-3-tony.luck@intel.com

diff --git a/arch/x86/include/asm/extable.h b/arch/x86/include/asm/extable.h
index d8c2198d543b460e3386afd2dbc1cb9961080738..1f0cbc52937ca571e6b517af01b988bbe218fff0 100644 (file)
--- a/arch/x86/include/asm/extable.h
+++ b/arch/x86/include/asm/extable.h
@@ -29,10 +29,17 @@ struct pt_regs;
                (b)->handler = (tmp).handler - (delta);         \
        } while (0)
 
+enum handler_type {
+       EX_HANDLER_NONE,
+       EX_HANDLER_FAULT,
+       EX_HANDLER_UACCESS,
+       EX_HANDLER_OTHER
+};
+
 extern int fixup_exception(struct pt_regs *regs, int trapnr,
                           unsigned long error_code, unsigned long fault_addr);
 extern int fixup_bug(struct pt_regs *regs, int trapnr);
-extern bool ex_has_fault_handler(unsigned long ip);
+extern enum handler_type ex_get_fault_handler_type(unsigned long ip);
 extern void early_fixup_exception(struct pt_regs *regs, int trapnr);
 
 #endif

diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 0b072dc231ad0cf41115e6fef7485734765d24f9..c6494e6579c1e90fd5798652bfd1d14178173354 100644 (file)
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -225,10 +225,13 @@ static struct severity {
  */
 static int error_context(struct mce *m, struct pt_regs *regs)
 {
+       enum handler_type t;
+
        if ((m->cs & 3) == 3)
                return IN_USER;
 
-       if (mc_recoverable(m->mcgstatus) && ex_has_fault_handler(m->ip)) {
+       t = ex_get_fault_handler_type(m->ip);
+       if (mc_recoverable(m->mcgstatus) && t == EX_HANDLER_FAULT) {
                m->kflags |= MCE_IN_KERNEL_RECOV;
                return IN_KERNEL_RECOV;
        }

diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 1d6cb07f4f86f55e4d2d6bea0d09356291206ee8..de43525df69b6a6d1522ea5edad5ad1691a390c7 100644 (file)
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -125,17 +125,21 @@ __visible bool ex_handler_clear_fs(const struct exception_table_entry *fixup,
 }
 EXPORT_SYMBOL(ex_handler_clear_fs);
 
-__visible bool ex_has_fault_handler(unsigned long ip)
+enum handler_type ex_get_fault_handler_type(unsigned long ip)
 {
        const struct exception_table_entry *e;
        ex_handler_t handler;
 
        e = search_exception_tables(ip);
        if (!e)
-               return false;
+               return EX_HANDLER_NONE;
        handler = ex_fixup_handler(e);
-
-       return handler == ex_handler_fault;
+       if (handler == ex_handler_fault)
+               return EX_HANDLER_FAULT;
+       else if (handler == ex_handler_uaccess)
+               return EX_HANDLER_UACCESS;
+       else
+               return EX_HANDLER_OTHER;
 }
 
 int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,