Merging upstream version 6.9.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 22 insertions, 77 deletions

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 70b91a8c6b..327855a11d 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -371,6 +371,21 @@ static struct break_hook kprobes_break_ss_hook = {
 	.fn = kprobe_breakpoint_ss_handler,
 };
 
+static int __kprobes
+kretprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)
+{
+	if (regs->pc != (unsigned long)__kretprobe_trampoline)
+		return DBG_HOOK_ERROR;
+
+	regs->pc = kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
+	return DBG_HOOK_HANDLED;
+}
+
+static struct break_hook kretprobes_break_hook = {
+	.imm = KRETPROBES_BRK_IMM,
+	.fn = kretprobe_breakpoint_handler,
+};
+
 /*
  * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
  * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
@@ -396,11 +411,6 @@ int __init arch_populate_kprobe_blacklist(void)
 	return ret;
 }
 
-void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
-{
-	return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
-}
-
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 				      struct pt_regs *regs)
 {
@@ -420,6 +430,7 @@ int __init arch_init_kprobes(void)
 {
 	register_kernel_break_hook(&kprobes_break_hook);
 	register_kernel_break_hook(&kprobes_break_ss_hook);
+	register_kernel_break_hook(&kretprobes_break_hook);
 
 	return 0;
 }
diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S
index 9a6499bed5..a362f3dbb3 100644
--- a/arch/arm64/kernel/probes/kprobes_trampoline.S
+++ b/arch/arm64/kernel/probes/kprobes_trampoline.S
@@ -4,83 +4,17 @@
  */
 
 #include <linux/linkage.h>
-#include <asm/asm-offsets.h>
+#include <asm/asm-bug.h>
 #include <asm/assembler.h>
 
 	.text
 
-	.macro	save_all_base_regs
-	stp x0, x1, [sp, #S_X0]
-	stp x2, x3, [sp, #S_X2]
-	stp x4, x5, [sp, #S_X4]
-	stp x6, x7, [sp, #S_X6]
-	stp x8, x9, [sp, #S_X8]
-	stp x10, x11, [sp, #S_X10]
-	stp x12, x13, [sp, #S_X12]
-	stp x14, x15, [sp, #S_X14]
-	stp x16, x17, [sp, #S_X16]
-	stp x18, x19, [sp, #S_X18]
-	stp x20, x21, [sp, #S_X20]
-	stp x22, x23, [sp, #S_X22]
-	stp x24, x25, [sp, #S_X24]
-	stp x26, x27, [sp, #S_X26]
-	stp x28, x29, [sp, #S_X28]
-	add x0, sp, #PT_REGS_SIZE
-	stp lr, x0, [sp, #S_LR]
-	/*
-	 * Construct a useful saved PSTATE
-	 */
-	mrs x0, nzcv
-	mrs x1, daif
-	orr x0, x0, x1
-	mrs x1, CurrentEL
-	orr x0, x0, x1
-	mrs x1, SPSel
-	orr x0, x0, x1
-	stp xzr, x0, [sp, #S_PC]
-	.endm
-
-	.macro	restore_all_base_regs
-	ldr x0, [sp, #S_PSTATE]
-	and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
-	msr nzcv, x0
-	ldp x0, x1, [sp, #S_X0]
-	ldp x2, x3, [sp, #S_X2]
-	ldp x4, x5, [sp, #S_X4]
-	ldp x6, x7, [sp, #S_X6]
-	ldp x8, x9, [sp, #S_X8]
-	ldp x10, x11, [sp, #S_X10]
-	ldp x12, x13, [sp, #S_X12]
-	ldp x14, x15, [sp, #S_X14]
-	ldp x16, x17, [sp, #S_X16]
-	ldp x18, x19, [sp, #S_X18]
-	ldp x20, x21, [sp, #S_X20]
-	ldp x22, x23, [sp, #S_X22]
-	ldp x24, x25, [sp, #S_X24]
-	ldp x26, x27, [sp, #S_X26]
-	ldp x28, x29, [sp, #S_X28]
-	.endm
-
 SYM_CODE_START(__kretprobe_trampoline)
-	sub sp, sp, #PT_REGS_SIZE
-
-	save_all_base_regs
-
-	/* Setup a frame pointer. */
-	add x29, sp, #S_FP
-
-	mov x0, sp
-	bl trampoline_probe_handler
 	/*
-	 * Replace trampoline address in lr with actual orig_ret_addr return
-	 * address.
+	 * Trigger a breakpoint exception. The PC will be adjusted by
+	 * kretprobe_breakpoint_handler(), and no subsequent instructions will
+	 * be executed from the trampoline.
 	 */
-	mov lr, x0
-
-	/* The frame pointer (x29) is restored with other registers. */
-	restore_all_base_regs
-
-	add sp, sp, #PT_REGS_SIZE
-	ret
-
+	brk #KRETPROBES_BRK_IMM
+	ASM_BUG()
 SYM_CODE_END(__kretprobe_trampoline)