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>
diff --git a/arch/parisc/include/asm/assembly.h b/arch/parisc/include/asm/assembly.h
index 0da8482..b3069fd 100644
--- a/arch/parisc/include/asm/assembly.h
+++ b/arch/parisc/include/asm/assembly.h
@@ -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
diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index e0a8235..4006964 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -59,12 +59,13 @@
/*
* 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 )\
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index e767ab7..a63bb179 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -649,10 +649,8 @@
/* 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 */
diff --git a/arch/parisc/lib/lusercopy.S b/arch/parisc/lib/lusercopy.S
index 6f2d935..a512f07 100644
--- a/arch/parisc/lib/lusercopy.S
+++ b/arch/parisc/lib/lusercopy.S
@@ -88,9 +88,7 @@
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 @@
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
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 0293588..df0d329 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -142,6 +142,12 @@
{
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;