Commit a05d54c4 authored by Tony Luck's avatar Tony Luck Committed by Borislav Petkov
Browse files

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: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201006210910.21062-3-tony.luck@intel.com
parent 41ce0564

arch/x86/include/asm/extable.h

+8 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/cpu/mce/severity.c

+4 −1
Original line number Diff line number Diff line
@@ -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;

	}

arch/x86/mm/extable.c

+8 −4
Original line number Diff line number Diff line
@@ -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,

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