diff options
| author | Stuart Menefy <stuart.menefy@st.com> | 2007-11-30 16:12:36 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2008-01-28 13:18:58 +0900 |
| commit | 1efe4ce3ca126da77e450d5a83f7201949d76f62 (patch) | |
| tree | fbae9902aa4103a9e86d06f841d580f24682e7b3 /arch/sh/kernel/cpu/sh3/entry.S | |
| parent | 53ff09422e5e7a6d6198b767c8f494e43ec8e3ae (diff) | |
sh: GUSA atomic rollback support.
This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/cpu/sh3/entry.S')
| -rw-r--r-- | arch/sh/kernel/cpu/sh3/entry.S | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S index 0d12a124055..4004073f98c 100644 --- a/arch/sh/kernel/cpu/sh3/entry.S +++ b/arch/sh/kernel/cpu/sh3/entry.S @@ -13,8 +13,9 @@ #include <linux/linkage.h> #include <asm/asm-offsets.h> #include <asm/thread_info.h> -#include <asm/cpu/mmu_context.h> #include <asm/unistd.h> +#include <asm/cpu/mmu_context.h> +#include <asm/page.h> ! NOTE: ! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address @@ -409,6 +410,27 @@ ENTRY(handle_exception) ! Using k0, k1 for scratch registers (r0_bank1, r1_bank), ! save all registers onto stack. ! + +#ifdef CONFIG_GUSA + ! Check for roll back gRB (User and Kernel) + mov r15, k0 + shll k0 + bf/s 1f + shll k0 + bf/s 1f + stc spc, k1 + stc r0_bank, k0 + cmp/hs k0, k1 ! test k1 (saved PC) >= k0 (saved r0) + bt/s 2f + stc r1_bank, k1 + + add #-2, k0 + add r15, k0 + ldc k0, spc ! PC = saved r0 + r15 - 2 +2: mov k1, r15 ! SP = r1 +1: +#endif + stc ssr, k0 ! Is it from kernel space? shll k0 ! Check MD bit (bit30) by shifting it into... shll k0 ! ...the T bit |