From c65a5480ff29198c241f11d39d9e34ab22c72c69 Mon Sep 17 00:00:00 2001 From: Atsushi Nemoto Date: Mon, 12 Nov 2007 02:05:18 +0900 Subject: [MIPS] Fix potential latency problem due to non-atomic cpu_wait. If an interrupt happened between checking of NEED_RESCHED and WAIT instruction, adjust EPC to restart from checking of NEED_RESCHED. Signed-off-by: Atsushi Nemoto Signed-off-by: Ralf Baechle --- arch/mips/kernel/genex.S | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'arch/mips/kernel/genex.S') diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S index c6ada98ee042..f886dd7f708e 100644 --- a/arch/mips/kernel/genex.S +++ b/arch/mips/kernel/genex.S @@ -20,6 +20,7 @@ #include #include #include +#include #define PANIC_PIC(msg) \ .set push; \ @@ -126,7 +127,42 @@ handle_vcei: __FINIT + .align 5 /* 32 byte rollback region */ +LEAF(r4k_wait) + .set push + .set noreorder + /* start of rollback region */ + LONG_L t0, TI_FLAGS($28) + nop + andi t0, _TIF_NEED_RESCHED + bnez t0, 1f + nop + nop + nop + .set mips3 + wait + /* end of rollback region (the region size must be power of two) */ + .set pop +1: + jr ra + END(r4k_wait) + + .macro BUILD_ROLLBACK_PROLOGUE handler + FEXPORT(rollback_\handler) + .set push + .set noat + MFC0 k0, CP0_EPC + PTR_LA k1, r4k_wait + ori k0, 0x1f /* 32 byte rollback region */ + xori k0, 0x1f + bne k0, k1, 9f + MTC0 k0, CP0_EPC +9: + .set pop + .endm + .align 5 +BUILD_ROLLBACK_PROLOGUE handle_int NESTED(handle_int, PT_SIZE, sp) #ifdef CONFIG_TRACE_IRQFLAGS /* @@ -201,6 +237,7 @@ NESTED(except_vec_ejtag_debug, 0, sp) * This prototype is copied to ebase + n*IntCtl.VS and patched * to invoke the handler */ +BUILD_ROLLBACK_PROLOGUE except_vec_vi NESTED(except_vec_vi, 0, sp) SAVE_SOME SAVE_AT -- cgit v1.2.3