[PARISC] Use FIXUP_BRANCH_CLOBBER to asm clobber list
Joel Soete noticed correctly that the fixup's clobbers must be listed
as the ASM clobbers. FIXUP_BRANCH in unaligned.c has a new macro which
lists all the clobbers in the fixup, we use this throughout the file
to simplify the process of listing clobbers in the future.
A missing "r1" clobber is added to our uaccess.h for the 64-bit
__put_kernel_asm. Interestingly this is a pretty serious bug since gcc
generates pretty good use of r1 as a temporary and the uses of
__put_kernel_asm are varied and dangerous if r1 is scratched during
an invalid write.
Signed-off-by: Joel Soete <soete.joel@tiscali.be>
Signed-off-by: Carlos O'Donell <carlos@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
diff --git a/arch/parisc/kernel/unaligned.c b/arch/parisc/kernel/unaligned.c
index de0a1b2..92328fb 100644
--- a/arch/parisc/kernel/unaligned.c
+++ b/arch/parisc/kernel/unaligned.c
@@ -43,6 +43,8 @@
"\tldil L%%" #lbl ", %%r1\n" \
"\tldo R%%" #lbl "(%%r1), %%r1\n" \
"\tbv,n %%r0(%%r1)\n"
+/* If you use FIXUP_BRANCH, then you must list this clobber */
+#define FIXUP_BRANCH_CLOBBER "r1"
/* 1111 1100 0000 0000 0001 0011 1100 0000 */
#define OPCODE1(a,b,c) ((a)<<26|(b)<<12|(c)<<6)
@@ -157,7 +159,7 @@
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
- : "r20" );
+ : "r20", FIXUP_BRANCH_CLOBBER );
DPRINTF("val = 0x" RFMT "\n", val);
@@ -202,7 +204,7 @@
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
- : "r19", "r20" );
+ : "r19", "r20", FIXUP_BRANCH_CLOBBER );
DPRINTF("val = 0x" RFMT "\n", val);
@@ -253,7 +255,7 @@
" .previous\n"
: "=r" (val), "=r" (ret)
: "0" (val), "r" (saddr), "r" (regs->isr)
- : "r19", "r20" );
+ : "r19", "r20", FIXUP_BRANCH_CLOBBER );
#else
{
unsigned long valh=0,vall=0;
@@ -287,7 +289,7 @@
" .previous\n"
: "=r" (valh), "=r" (vall), "=r" (ret)
: "0" (valh), "1" (vall), "r" (saddr), "r" (regs->isr)
- : "r19", "r20" );
+ : "r19", "r20", FIXUP_BRANCH_CLOBBER );
val=((__u64)valh<<32)|(__u64)vall;
}
#endif
@@ -335,7 +337,7 @@
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
- : "r19" );
+ : "r19", FIXUP_BRANCH_CLOBBER );
return ret;
}
@@ -389,7 +391,7 @@
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
- : "r19", "r20", "r21", "r22", "r1" );
+ : "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER );
return 0;
}
@@ -450,7 +452,7 @@
" .previous\n"
: "=r" (ret)
: "r" (val), "r" (regs->ior), "r" (regs->isr)
- : "r19", "r20", "r21", "r22", "r1" );
+ : "r19", "r20", "r21", "r22", "r1", FIXUP_BRANCH_CLOBBER );
#else
{
unsigned long valh=(val>>32),vall=(val&0xffffffffl);
@@ -495,7 +497,7 @@
" .previous\n"
: "=r" (ret)
: "r" (valh), "r" (vall), "r" (regs->ior), "r" (regs->isr)
- : "r19", "r20", "r21", "r1" );
+ : "r19", "r20", "r21", "r1", FIXUP_BRANCH_CLOBBER );
}
#endif
diff --git a/include/asm-parisc/uaccess.h b/include/asm-parisc/uaccess.h
index f6c417c..d973e8b 100644
--- a/include/asm-parisc/uaccess.h
+++ b/include/asm-parisc/uaccess.h
@@ -172,7 +172,11 @@
/*
* The "__put_user/kernel_asm()" macros tell gcc they read from memory
* instead of writing. This is because they do not write to any memory
- * gcc knows about, so there are no aliasing issues.
+ * gcc knows about, so there are no aliasing issues. These macros must
+ * also be aware that "fixup_put_user_skip_[12]" are executed in the
+ * context of the fault, and any registers used there must be listed
+ * as clobbers. In this case only "r1" is used by the current routines.
+ * r8/r9 are already listed as err/val.
*/
#ifdef __LP64__
@@ -183,7 +187,8 @@
"\t.dword\t1b,fixup_put_user_skip_1\n" \
"\t.previous" \
: "=r"(__pu_err) \
- : "r"(ptr), "r"(x), "0"(__pu_err))
+ : "r"(ptr), "r"(x), "0"(__pu_err) \
+ : "r1")
#define __put_user_asm(stx,x,ptr) \
__asm__ __volatile__ ( \