What about EXCLR() in asmmacro.h? Doesn't that need to be updated as well? Did you verify that the equivalent isn't open-coded in any assembly-file? --david On 6/15/06, Masami Hiramatsu <hiramatu@xxxxxxxxxxxxxxxxx> wrote:
Hi, Tony
I found a suspicious buggy code in the linux kernel on IA64 arch.
As far as I can see, search_extable() doesn't work correctly, because
the lookup routine expects that the address format of the
exception_table_entry is "IP + slot", but the compiler (gcc-3.4.5)
generates it as "IP + (slot << 2)". Thus the lookup routine always
fails to find the corresponding entry.
You can check it by dumping __ex_table section of vmlinux.
I made a patch to fix this bug attached in this mail. This patch is
against 2.6.17-rc6-mm2.
Please review it.
Description:
Fix search_extable() and ia64_handle_exception() to handle the
address format of exception_table_entry correctly.
Thanks,
--
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: hiramatu@xxxxxxxxxxxxxxxxx
Signed-off-by: Masami Hiramatsu <hiramatu@xxxxxxxxxxxxxxxxx>
arch/ia64/mm/extable.c | 7 ++++---
include/asm-ia64/uaccess.h | 4 ++--
2 files changed, 6 insertions(+), 5 deletions(-)
diff --exclude=CVS -Narup a/arch/ia64/mm/extable.c b/arch/ia64/mm/extable.c
--- a/arch/ia64/mm/extable.c 2005-10-28 09:02:08.000000000 +0900
+++ b/arch/ia64/mm/extable.c 2006-06-14 14:59:11.000000000 +0900
@@ -63,9 +63,10 @@ search_extable (const struct exception_t
unsigned long mid_ip;
long diff;
+ ip = (ip & ~0xf) + ((ip & 0x3) << 2);
while (first <= last) {
mid = &first[(last - first)/2];
- mid_ip = (u64) &mid->addr + mid->addr;
+ mid_ip = ((u64) &mid->addr + mid->addr) & ~0x3;
diff = mid_ip - ip;
if (diff == 0)
return mid;
@@ -83,8 +84,8 @@ ia64_handle_exception (struct pt_regs *r
long fix = (u64) &e->cont + e->cont;
regs->r8 = -EFAULT;
- if (fix & 4)
+ if (fix & 2)
regs->r9 = 0;
regs->cr_iip = fix & ~0xf;
- ia64_psr(regs)->ri = fix & 0x3; /* set continuation slot number */
+ ia64_psr(regs)->ri = (fix & 0xc) >> 2; /* set continuation slot number */
}
diff --exclude=CVS -Narup a/include/asm-ia64/uaccess.h b/include/asm-ia64/uaccess.h
--- a/include/asm-ia64/uaccess.h 2005-10-28 09:02:08.000000000 +0900
+++ b/include/asm-ia64/uaccess.h 2006-06-14 23:54:55.000000000 +0900
@@ -139,7 +139,7 @@ do { \
register long __gu_r8 asm ("r8") = 0; \
register long __gu_r9 asm ("r9"); \
asm ("\n[1:]\tld"#n" %0=%2%P2\t// %0 and %1 get overwritten by exception handler\n" \
- "\t.xdata4 \"__ex_table\", 1b-., 1f-.+4\n" \
+ "\t.xdata4 \"__ex_table\", 1b-., 1f-.+2\n" \
"[1:]" \
: "=r"(__gu_r9), "=r"(__gu_r8) : "m"(__m(addr)), "1"(__gu_r8)); \
(err) = __gu_r8; \
@@ -346,7 +346,7 @@ extern unsigned long __strnlen_user (con
struct exception_table_entry {
int addr; /* location-relative address of insn this fixup is for */
- int cont; /* location-relative continuation addr.; if bit 2 is set, r9 is set to 0 */
+ int cont; /* location-relative continuation addr.; if bit 1 is set, r9 is set to 0 */
};
extern void ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e);
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