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authorTiezhu Yang <yangtiezhu@loongson.cn>2021-02-09 13:05:25 +0800
committerThomas Bogendoerfer <tsbogend@alpha.franken.de>2021-02-11 11:04:31 +0100
commitee54d379fc9c490797aa71d25d0320b5af5924a1 (patch)
treedec1f2d42a36d1205e41e31b687c629ac0cc71a5 /arch/mips
parente66ef72d269105cee2ae9c8fa0442d7a9857324f (diff)
MIPS: Make check condition for SDBBP consistent with EJTAG spec
According to MIPS EJTAG Specification [1], a Debug Breakpoint exception occurs when an SDBBP instruction is executed, the CP0_DEBUG bit DBp indicates that a Debug Breakpoint exception occurred. When I read the original code, it looks a little confusing at first glance, just check bit DBp for SDBBP to make the code more readable, it will be much easier to understand. [1] http://www.t-es-t.hu/download/mips/md00047f.pdf Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/include/asm/mipsregs.h4
-rw-r--r--arch/mips/kernel/genex.S4
2 files changed, 6 insertions, 2 deletions
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index a0e8ae5497b6..9c8099a6ffed 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -1085,6 +1085,10 @@
#define CVMVMCONF_RMMUSIZEM1_S 0
#define CVMVMCONF_RMMUSIZEM1 (_U64CAST_(0xff) << CVMVMCONF_RMMUSIZEM1_S)
+/* Debug register field definitions */
+#define MIPS_DEBUG_DBP_SHIFT 1
+#define MIPS_DEBUG_DBP (_ULCAST_(1) << MIPS_DEBUG_DBP_SHIFT)
+
/*
* Coprocessor 1 (FPU) register names
*/
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index bcce32a3de10..743d75927b71 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -349,8 +349,8 @@ NESTED(ejtag_debug_handler, PT_SIZE, sp)
MTC0 k0, CP0_DESAVE
mfc0 k0, CP0_DEBUG
- sll k0, k0, 30 # Check for SDBBP.
- bgez k0, ejtag_return
+ andi k0, k0, MIPS_DEBUG_DBP # Check for SDBBP.
+ beqz k0, ejtag_return
#ifdef CONFIG_SMP
1: PTR_LA k0, ejtag_debug_buffer_spinlock