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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: Helge Deller <deller@gmx.de>
This commit is contained in:
Helge Deller 2013-10-13 21:11:30 +02:00
parent 5e01dc7b26
commit 61dbbaeb86
5 changed files with 27 additions and 14 deletions
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12
arch/parisc/include/asm/assembly.h
View File

@ -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

7
arch/parisc/include/asm/uaccess.h
View File

@ -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 insn; /* address of insn that is allowed to fault. */
unsigned long fixup; /* fixup routine */
};
#define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\

6
arch/parisc/kernel/syscall.S
View File

@ -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 */

10
arch/parisc/lib/lusercopy.S
View File

@ -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

6
arch/parisc/mm/fault.c
View File

@ -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;