* [PATCH 4/9] mips: deal with larger physical offsets
@ 2009-06-01 11:59 Florian Fainelli
2009-06-01 18:13 ` David Daney
0 siblings, 1 reply; 2+ messages in thread
From: Florian Fainelli @ 2009-06-01 11:59 UTC (permalink / raw)
To: linux-mips, Ralf Baechle
TI AR7 has larger physical offsets than other MIPS-based
systems. A long jump to the target is required instead of
a short jump like on other systems.
Signed-off-by: Eugene Konev <ejka@imfi.kspu.ru>
Signed-off-by: Florian Fainelli <florian@openwrt.org>
---
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index e83da17..44f7141 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -1256,9 +1256,22 @@ void *set_except_vector(int n, void *addr)
exception_handlers[n] = handler;
if (n == 0 && cpu_has_divec) {
- *(u32 *)(ebase + 0x200) = 0x08000000 |
- (0x03ffffff & (handler >> 2));
- local_flush_icache_range(ebase + 0x200, ebase + 0x204);
+ if ((handler ^ (ebase + 4)) & 0xfc000000) {
+ /* lui k0, 0x0000 */
+ *(u32 *)(ebase + 0x200) = 0x3c1a0000 | (handler >> 16);
+ /* ori k0, 0x0000 */
+ *(u32 *)(ebase + 0x204) =
+ 0x375a0000 | (handler & 0xffff);
+ /* jr k0 */
+ *(u32 *)(ebase + 0x208) = 0x03400008;
+ /* nop */
+ *(u32 *)(ebase + 0x20C) = 0x00000000;
+ local_flush_icache_range(ebase + 0x200, ebase + 0x210);
+ } else {
+ *(u32 *)(ebase + 0x200) =
+ 0x08000000 | (0x03ffffff & (handler >> 2));
+ local_flush_icache_range(ebase + 0x200, ebase + 0x204);
+ }
}
return (void *)old_handler;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 4/9] mips: deal with larger physical offsets
2009-06-01 11:59 [PATCH 4/9] mips: deal with larger physical offsets Florian Fainelli
@ 2009-06-01 18:13 ` David Daney
0 siblings, 0 replies; 2+ messages in thread
From: David Daney @ 2009-06-01 18:13 UTC (permalink / raw)
To: Florian Fainelli, Ralf Baechle; +Cc: linux-mips
Florian Fainelli wrote:
> TI AR7 has larger physical offsets than other MIPS-based
> systems. A long jump to the target is required instead of
> a short jump like on other systems.
>
> Signed-off-by: Eugene Konev <ejka@imfi.kspu.ru>
> Signed-off-by: Florian Fainelli <florian@openwrt.org>
> ---
> diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
> index e83da17..44f7141 100644
> --- a/arch/mips/kernel/traps.c
> +++ b/arch/mips/kernel/traps.c
> @@ -1256,9 +1256,22 @@ void *set_except_vector(int n, void *addr)
>
> exception_handlers[n] = handler;
> if (n == 0 && cpu_has_divec) {
> - *(u32 *)(ebase + 0x200) = 0x08000000 |
> - (0x03ffffff & (handler >> 2));
> - local_flush_icache_range(ebase + 0x200, ebase + 0x204);
> + if ((handler ^ (ebase + 4)) & 0xfc000000) {
> + /* lui k0, 0x0000 */
> + *(u32 *)(ebase + 0x200) = 0x3c1a0000 | (handler >> 16);
> + /* ori k0, 0x0000 */
> + *(u32 *)(ebase + 0x204) =
> + 0x375a0000 | (handler & 0xffff);
> + /* jr k0 */
> + *(u32 *)(ebase + 0x208) = 0x03400008;
> + /* nop */
> + *(u32 *)(ebase + 0x20C) = 0x00000000;
> + local_flush_icache_range(ebase + 0x200, ebase + 0x210);
> + } else {
> + *(u32 *)(ebase + 0x200) =
> + 0x08000000 | (0x03ffffff & (handler >> 2));
> + local_flush_icache_range(ebase + 0x200, ebase + 0x204);
> + }
> }
> return (void *)old_handler;
> }
>
I had to do a similar change for my mapped kernel patch. However in
mine, I used uasm. I wonder if the extra memory occupied by uasm is too
steep a penalty to pay for the ability to use it outside of __init code.
If not, we should move uasm out of __init and use it instead of this
manual assembly.
David Daney
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