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Commit 61dbbaeb authored by Helge Deller's avatar Helge Deller
Browse files

parisc: provide macro to create exception table entries 



Provide a macro ASM_EXCEPTIONTABLE_ENTRY() to create exception table
entries and convert all open-coded places to use that macro.

This patch is a first step toward creating a exception table which only
holds 32bit pointers even on a 64bit kernel. That way in my own kernel
I was able to reduce the in-kernel exception table from 44kB to 22kB.

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 5e01dc7b

arch/parisc/include/asm/assembly.h

+12 −0
Original line number Diff line number Diff line
@@ -515,5 +515,17 @@ 
	nop	/* 7 */

	.endm



	/*

	 * ASM_EXCEPTIONTABLE_ENTRY

	 *

	 * Creates an exception table entry.

	 * Do not convert to a assembler macro. This won't work.

	 */

#define ASM_EXCEPTIONTABLE_ENTRY(fault_addr, except_addr)	\

	.section __ex_table,"aw"			!	\

	ASM_ULONG_INSN	fault_addr, except_addr		!	\

	.previous





#endif /* __ASSEMBLY__ */

#endif

arch/parisc/include/asm/uaccess.h

+4 −3
Original line number Diff line number Diff line
@@ -59,12 +59,13 @@ static inline long access_ok(int type, const void __user * addr, 
/*

 * The exception table contains two values: the first is an address

 * for an instruction that is allowed to fault, and the second is

 * the address to the fixup routine. 

 * the address to the fixup routine. Even on a 64bit kernel we could

 * use a 32bit (unsigned int) address here.

 */



struct exception_table_entry {

	unsigned long insn;	/* address of insn that is allowed to fault. */

	long fixup;          /* fixup routine */

	unsigned long fixup;	/* fixup routine */

};



#define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\

arch/parisc/kernel/syscall.S

+2 −4
Original line number Diff line number Diff line
@@ -649,10 +649,8 @@ cas_action: 
	/* Two exception table entries, one for the load,

	   the other for the store. Either return -EFAULT.

	   Each of the entries must be relocated. */

	.section __ex_table,"aw"

	ASM_ULONG_INSN (1b - linux_gateway_page), (3b - linux_gateway_page)

	ASM_ULONG_INSN (2b - linux_gateway_page), (3b - linux_gateway_page)

	.previous

	ASM_EXCEPTIONTABLE_ENTRY(1b-linux_gateway_page, 3b-linux_gateway_page)

	ASM_EXCEPTIONTABLE_ENTRY(2b-linux_gateway_page, 3b-linux_gateway_page)





	/* Make sure nothing else is placed on this page */

arch/parisc/lib/lusercopy.S

+3 −7
Original line number Diff line number Diff line
@@ -88,9 +88,7 @@ ENDPROC(lclear_user) 
	ldo        1(%r25),%r25

	.previous



	.section __ex_table,"aw"

	ASM_ULONG_INSN 1b,2b

	.previous

	ASM_EXCEPTIONTABLE_ENTRY(1b,2b)



	.procend
@@ -129,10 +127,8 @@ ENDPROC(lstrnlen_user) 
	copy        %r24,%r26    /* reset r26 so 0 is returned on fault */

	.previous



	.section __ex_table,"aw"

	ASM_ULONG_INSN 1b,3b

	ASM_ULONG_INSN 2b,3b

	.previous

	ASM_EXCEPTIONTABLE_ENTRY(1b,3b)

	ASM_EXCEPTIONTABLE_ENTRY(2b,3b)



	.procend

arch/parisc/mm/fault.c

+6 −0
Original line number Diff line number Diff line
@@ -142,6 +142,12 @@ int fixup_exception(struct pt_regs *regs) 
{

	const struct exception_table_entry *fix;



	/* If we only stored 32bit addresses in the exception table we can drop

	 * out if we faulted on a 64bit address. */

	if ((sizeof(regs->iaoq[0]) > sizeof(fix->insn))

		&& (regs->iaoq[0] >> 32))

			return 0;



	fix = search_exception_tables(regs->iaoq[0]);

	if (fix) {

		struct exception_data *d;