powerpc: Add support for relative exception tables
This halves the exception table size on 64-bit builds, and it allows
build-time sorting of exception tables to work on relocated kernels.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Minor asm fixups and bits to keep the selftests working]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 6af8852..bf9de55 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -785,9 +785,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_601)
*/
#define EX_TABLE(_fault, _target) \
stringify_in_c(.section __ex_table,"a";)\
- PPC_LONG_ALIGN stringify_in_c(;) \
- PPC_LONG stringify_in_c(_fault;) \
- PPC_LONG stringify_in_c(_target;) \
+ stringify_in_c(.balign 4;) \
+ stringify_in_c(.long (_fault) - . ;) \
+ stringify_in_c(.long (_target) - . ;) \
stringify_in_c(.previous)
#endif /* _ASM_POWERPC_PPC_ASM_H */
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index e0b7246..a15d84d 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -64,23 +64,30 @@
__access_ok((__force unsigned long)(addr), (size), get_fs()))
/*
- * The exception table consists of pairs of addresses: the first is the
- * address of an instruction that is allowed to fault, and the second is
+ * The exception table consists of pairs of relative addresses: the first is
+ * the address of an instruction that is allowed to fault, and the second is
* the address at which the program should continue. No registers are
- * modified, so it is entirely up to the continuation code to figure out
- * what to do.
+ * modified, so it is entirely up to the continuation code to figure out what
+ * to do.
*
- * All the routines below use bits of fixup code that are out of line
- * with the main instruction path. This means when everything is well,
- * we don't even have to jump over them. Further, they do not intrude
- * on our cache or tlb entries.
+ * All the routines below use bits of fixup code that are out of line with the
+ * main instruction path. This means when everything is well, we don't even
+ * have to jump over them. Further, they do not intrude on our cache or tlb
+ * entries.
*/
+#define ARCH_HAS_RELATIVE_EXTABLE
+
struct exception_table_entry {
- unsigned long insn;
- unsigned long fixup;
+ int insn;
+ int fixup;
};
+static inline unsigned long extable_fixup(const struct exception_table_entry *x)
+{
+ return (unsigned long)&x->fixup + x->fixup;
+}
+
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index e785cc9..9479d8e 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -449,7 +449,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
* zero, try to fix up.
*/
if ((entry = search_exception_tables(regs->nip)) != NULL) {
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return 1;
}
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 023a462..32c468b 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -365,7 +365,7 @@ static inline int check_io_access(struct pt_regs *regs)
(*nip & 0x100)? "OUT to": "IN from",
regs->gpr[rb] - _IO_BASE, nip);
regs->msr |= MSR_RI;
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return 1;
}
}
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index d0b137d..73932f4 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -512,7 +512,7 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
/* Are we prepared to handle this fault? */
if ((entry = search_exception_tables(regs->nip)) != NULL) {
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return;
}
diff --git a/arch/powerpc/platforms/embedded6xx/holly.c b/arch/powerpc/platforms/embedded6xx/holly.c
index dfd3100..0409714 100644
--- a/arch/powerpc/platforms/embedded6xx/holly.c
+++ b/arch/powerpc/platforms/embedded6xx/holly.c
@@ -263,7 +263,7 @@ static int ppc750_machine_check_exception(struct pt_regs *regs)
if ((entry = search_exception_tables(regs->nip)) != NULL) {
tsi108_clear_pci_cfg_error();
regs->msr |= MSR_RI;
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return 1;
}
return 0;
diff --git a/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c b/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
index f97bab8..9de100e 100644
--- a/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
+++ b/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
@@ -174,7 +174,7 @@ static int mpc7448_machine_check_exception(struct pt_regs *regs)
if ((entry = search_exception_tables(regs->nip)) != NULL) {
tsi108_clear_pci_cfg_error();
regs->msr |= MSR_RI;
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return 1;
}
return 0;
diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index 87fee0c..1c41c51 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -111,7 +111,7 @@ int fsl_rio_mcheck_exception(struct pt_regs *regs)
out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
0);
regs->msr |= MSR_RI;
- regs->nip = entry->fixup;
+ regs->nip = extable_fixup(entry);
return 1;
}
}