arm64: probes: Move magic BRK values into brk-imm.h

kprobes and uprobes reserve some BRK immediates for installing their probes. Define these along with the other reservations in brk-imm.h and rename the ESR definitions to be consistent with the others that we already have. Reviewed-by: Mark Rutland <[email protected]> Signed-off-by: Will Deacon <[email protected]>
nelseric · Apr 9, 2019 · 453b774 · 453b774
1 parent fb610f2
commit 453b774
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Showing 7 changed files with 11 additions and 12 deletions.
diff --git a/arch/arm64/include/asm/brk-imm.h b/arch/arm64/include/asm/brk-imm.h
@@ -11,13 +11,17 @@
 
 /*
  * #imm16 values used for BRK instruction generation
+ * 0x004: for installing kprobes
+ * 0x005: for installing uprobes
  * Allowed values for kgdb are 0x400 - 0x7ff
  * 0x100: for triggering a fault on purpose (reserved)
  * 0x400: for dynamic BRK instruction
  * 0x401: for compile time BRK instruction
  * 0x800: kernel-mode BUG() and WARN() traps
  * 0x9xx: tag-based KASAN trap (allowed values 0x900 - 0x9ff)
  */
+#define KPROBES_BRK_IMM			0x004
+#define UPROBES_BRK_IMM			0x005
 #define FAULT_BRK_IMM			0x100
 #define KGDB_DYN_DBG_BRK_IMM		0x400
 #define KGDB_COMPILED_DBG_BRK_IMM	0x401

diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
@@ -65,12 +65,9 @@
 #define CACHE_FLUSH_IS_SAFE		1
 
 /* kprobes BRK opcodes with ESR encoding  */
-#define BRK64_ESR_MASK		0xFFFF
-#define BRK64_ESR_KPROBES	0x0004
-#define BRK64_OPCODE_KPROBES	(AARCH64_BREAK_MON | (BRK64_ESR_KPROBES << 5))
+#define BRK64_OPCODE_KPROBES	(AARCH64_BREAK_MON | (KPROBES_BRK_IMM << 5))
 /* uprobes BRK opcodes with ESR encoding  */
-#define BRK64_ESR_UPROBES	0x0005
-#define BRK64_OPCODE_UPROBES	(AARCH64_BREAK_MON | (BRK64_ESR_UPROBES << 5))
+#define BRK64_OPCODE_UPROBES	(AARCH64_BREAK_MON | (UPROBES_BRK_IMM << 5))
 
 /* AArch32 */
 #define DBG_ESR_EVT_BKPT	0x4

diff --git a/arch/arm64/include/asm/esr.h b/arch/arm64/include/asm/esr.h
@@ -156,9 +156,7 @@
 				 ESR_ELx_WFx_ISS_WFI)
 
 /* BRK instruction trap from AArch64 state */
-#define ESR_ELx_VAL_BRK64(imm)					\
-	((ESR_ELx_EC_BRK64 << ESR_ELx_EC_SHIFT) | ESR_ELx_IL |	\
-	 ((imm) & 0xffff))
+#define ESR_ELx_BRK64_ISS_COMMENT_MASK	0xffff
 
 /* ISS field definitions for System instruction traps */
 #define ESR_ELx_SYS64_ISS_RES0_SHIFT	22

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
@@ -317,7 +317,7 @@ static int call_break_hook(struct pt_regs *regs, unsigned int esr)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(hook, list, node) {
-		unsigned int comment = esr & BRK64_ESR_MASK;
+		unsigned int comment = esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
 
 		if ((comment & ~hook->mask) == hook->imm)
 			fn = hook->fn;

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
@@ -470,7 +470,7 @@ kprobe_breakpoint_handler(struct pt_regs *regs, unsigned int esr)
 }
 
 static struct break_hook kprobes_break_hook = {
-	.imm = BRK64_ESR_KPROBES,
+	.imm = KPROBES_BRK_IMM,
 	.fn = kprobe_breakpoint_handler,
 };
 

diff --git a/arch/arm64/kernel/probes/uprobes.c b/arch/arm64/kernel/probes/uprobes.c
@@ -191,7 +191,7 @@ static int uprobe_single_step_handler(struct pt_regs *regs,
 
 /* uprobe breakpoint handler hook */
 static struct break_hook uprobes_break_hook = {
-	.imm = BRK64_ESR_UPROBES,
+	.imm = UPROBES_BRK_IMM,
 	.fn = uprobe_breakpoint_handler,
 };
 

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
@@ -1024,7 +1024,7 @@ int __init early_brk64(unsigned long addr, unsigned int esr,
 		struct pt_regs *regs)
 {
 #ifdef CONFIG_KASAN_SW_TAGS
-	unsigned int comment = esr & BRK64_ESR_MASK;
+	unsigned int comment = esr & ESR_ELx_BRK64_ISS_COMMENT_MASK;
 
 	if ((comment & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
 		return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;