From: Andrei Vagin <avagin@gmail.com>
To: Will Deacon <will@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Andrei Vagin <avagin@gmail.com>
Subject: [PATCH 2/3] arm64/ptrace: introduce NT_ARM_PRSTATUS to get a full set of registers
Date: Tue, 19 Jan 2021 14:06:36 -0800 [thread overview]
Message-ID: <20210119220637.494476-3-avagin@gmail.com> (raw)
In-Reply-To: <20210119220637.494476-1-avagin@gmail.com>
This is an alternative to NT_PRSTATUS that clobbers ip/r12 on AArch32,
x7 on AArch64 when a tracee is stopped in syscall entry or syscall exit
traps.
Signed-off-by: Andrei Vagin <avagin@gmail.com>
---
arch/arm64/kernel/ptrace.c | 39 ++++++++++++++++++++++++++++++++++++++
include/uapi/linux/elf.h | 1 +
2 files changed, 40 insertions(+)
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 1863f080cb07..b8e4c2ddf636 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -591,6 +591,15 @@ static int gpr_get(struct task_struct *target,
return ret;
}
+static int gpr_get_full(struct task_struct *target,
+ const struct user_regset *regset,
+ struct membuf to)
+{
+ struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
+
+ return membuf_write(&to, uregs, sizeof(*uregs));
+}
+
static int gpr_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
@@ -1088,6 +1097,7 @@ static int tagged_addr_ctrl_set(struct task_struct *target, const struct
enum aarch64_regset {
REGSET_GPR,
+ REGSET_GPR_FULL,
REGSET_FPR,
REGSET_TLS,
#ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -1119,6 +1129,14 @@ static const struct user_regset aarch64_regsets[] = {
.regset_get = gpr_get,
.set = gpr_set
},
+ [REGSET_GPR_FULL] = {
+ .core_note_type = NT_ARM_PRSTATUS,
+ .n = sizeof(struct user_pt_regs) / sizeof(u64),
+ .size = sizeof(u64),
+ .align = sizeof(u64),
+ .regset_get = gpr_get_full,
+ .set = gpr_set
+ },
[REGSET_FPR] = {
.core_note_type = NT_PRFPREG,
.n = sizeof(struct user_fpsimd_state) / sizeof(u32),
@@ -1225,6 +1243,7 @@ static const struct user_regset_view user_aarch64_view = {
#ifdef CONFIG_COMPAT
enum compat_regset {
REGSET_COMPAT_GPR,
+ REGSET_COMPAT_GPR_FULL,
REGSET_COMPAT_VFP,
};
@@ -1285,6 +1304,18 @@ static int compat_gpr_get(struct task_struct *target,
return 0;
}
+/* compat_gpr_get_full doesn't overwrite x12 like compat_gpr_get. */
+static int compat_gpr_get_full(struct task_struct *target,
+ const struct user_regset *regset,
+ struct membuf to)
+{
+ int i = 0;
+
+ while (to.left)
+ membuf_store(&to, compat_get_user_reg(target, i++));
+ return 0;
+}
+
static int compat_gpr_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
@@ -1435,6 +1466,14 @@ static const struct user_regset aarch32_regsets[] = {
.regset_get = compat_gpr_get,
.set = compat_gpr_set
},
+ [REGSET_COMPAT_GPR_FULL] = {
+ .core_note_type = NT_ARM_PRSTATUS,
+ .n = COMPAT_ELF_NGREG,
+ .size = sizeof(compat_elf_greg_t),
+ .align = sizeof(compat_elf_greg_t),
+ .regset_get = compat_gpr_get_full,
+ .set = compat_gpr_set
+ },
[REGSET_COMPAT_VFP] = {
.core_note_type = NT_ARM_VFP,
.n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index 30f68b42eeb5..a2086d19263a 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -426,6 +426,7 @@ typedef struct elf64_shdr {
#define NT_ARM_PACA_KEYS 0x407 /* ARM pointer authentication address keys */
#define NT_ARM_PACG_KEYS 0x408 /* ARM pointer authentication generic key */
#define NT_ARM_TAGGED_ADDR_CTRL 0x409 /* arm64 tagged address control (prctl()) */
+#define NT_ARM_PRSTATUS 0x410 /* ARM general-purpose registers */
#define NT_ARC_V2 0x600 /* ARCv2 accumulator/extra registers */
#define NT_VMCOREDD 0x700 /* Vmcore Device Dump Note */
#define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */
--
2.29.2
next prev parent reply other threads:[~2021-01-19 22:12 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-19 22:06 [PATCH 0/3] arm64/ptrace: allow to get all registers on syscall traps Andrei Vagin
2021-01-19 22:06 ` [PATCH 1/3] arm64/ptrace: don't clobber task registers on syscall entry/exit traps Andrei Vagin
2021-01-27 15:14 ` Dave Martin
2021-01-19 22:06 ` Andrei Vagin [this message]
2021-01-27 14:53 ` [PATCH 2/3] arm64/ptrace: introduce NT_ARM_PRSTATUS to get a full set of registers Dave Martin
2021-01-29 7:56 ` Andrei Vagin
2021-01-19 22:06 ` [PATCH 3/3] selftest/arm64/ptrace: add a test for NT_ARM_PRSTATUS Andrei Vagin
2021-01-27 8:10 ` [PATCH 0/3] arm64/ptrace: allow to get all registers on syscall traps Andrei Vagin
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