[PATCH v3 2/6] syscall.h: add syscall_set_arguments() and syscall_set_return_value()

Dmitry V. Levin
2025-01-28T09:16:38Z

These functions are going to be needed on all HAVE_ARCH_TRACEHOOK
architectures to implement PTRACE_SET_SYSCALL_INFO API.

This partially reverts commit 7962c2eddbfe ("arch: remove unused
function syscall_set_arguments()") by reusing some of old
syscall_set_arguments() implementations.

Signed-off-by: Dmitry V. Levin <ldv@strace.io>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
---
arch/arc/include/asm/syscall.h | 14 +++++++++++
arch/arm/include/asm/syscall.h | 13 ++++++++++
arch/arm64/include/asm/syscall.h | 13 ++++++++++
arch/csky/include/asm/syscall.h | 13 ++++++++++
arch/hexagon/include/asm/syscall.h | 14 +++++++++++
arch/loongarch/include/asm/syscall.h | 8 ++++++
arch/mips/include/asm/syscall.h | 32 ++++++++++++++++++++++++
arch/nios2/include/asm/syscall.h | 11 ++++++++
arch/openrisc/include/asm/syscall.h | 7 ++++++
arch/parisc/include/asm/syscall.h | 12 +++++++++
arch/powerpc/include/asm/syscall.h | 10 ++++++++
arch/riscv/include/asm/syscall.h | 9 +++++++
arch/s390/include/asm/syscall.h | 12 +++++++++
arch/sh/include/asm/syscall_32.h | 12 +++++++++
arch/sparc/include/asm/syscall.h | 10 ++++++++
arch/um/include/asm/syscall-generic.h | 14 +++++++++++
arch/x86/include/asm/syscall.h | 36 +++++++++++++++++++++++++++
arch/xtensa/include/asm/syscall.h | 11 ++++++++
include/asm-generic/syscall.h | 16 ++++++++++++
19 files changed, 267 insertions(+)

diff --git a/arch/arc/include/asm/syscall.h b/arch/arc/include/asm/syscall.h
index 9709256e31c8..89c1e1736356 100644
--- a/arch/arc/include/asm/syscall.h
+++ b/arch/arc/include/asm/syscall.h
@@ -67,6 +67,20 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
}
}

+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+ unsigned long *args)
+{
+ unsigned long *inside_ptregs = &regs->r0;
+ unsigned int n = 6;
+ unsigned int i = 0;
+
+ while (n--) {
+ *inside_ptregs = args[i++];
+ inside_ptregs--;
+ }
+}
+
static inline int
syscall_get_arch(struct task_struct *task)
{
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index fe4326d938c1..21927fa0ae2b 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -80,6 +80,19 @@ static inline void syscall_get_arguments(struct task_struct *task,
memcpy(args, &regs->ARM_r0 + 1, 5 * sizeof(args[0]));
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ memcpy(&regs->ARM_r0, args, 6 * sizeof(args[0]));
+ /*
+ * Also copy the first argument into ARM_ORIG_r0
+ * so that syscall_get_arguments() would return it
+ * instead of the previous value.
+ */
+ regs->ARM_ORIG_r0 = regs->ARM_r0;
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
/* ARM tasks don't change audit architectures on the fly. */
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index ab8e14b96f68..76020b66286b 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -73,6 +73,19 @@ static inline void syscall_get_arguments(struct task_struct *task,
memcpy(args, &regs->regs[1], 5 * sizeof(args[0]));
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ memcpy(&regs->regs[0], args, 6 * sizeof(args[0]));
+ /*
+ * Also copy the first argument into orig_x0
+ * so that syscall_get_arguments() would return it
+ * instead of the previous value.
+ */
+ regs->orig_x0 = regs->regs[0];
+}
+
/*
* We don't care about endianness (__AUDIT_ARCH_LE bit) here because
* AArch64 has the same system calls both on little- and big- endian.
diff --git a/arch/csky/include/asm/syscall.h b/arch/csky/include/asm/syscall.h
index 0de5734950bf..30403f7a0487 100644
--- a/arch/csky/include/asm/syscall.h
+++ b/arch/csky/include/asm/syscall.h
@@ -59,6 +59,19 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
memcpy(args, &regs->a1, 5 * sizeof(args[0]));
}

+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+ const unsigned long *args)
+{
+ memcpy(&regs->a0, args, 6 * sizeof(regs->a0));
+ /*
+ * Also copy the first argument into orig_x0
+ * so that syscall_get_arguments() would return it
+ * instead of the previous value.
+ */
+ regs->orig_a0 = regs->a0;
+}
+
static inline int
syscall_get_arch(struct task_struct *task)
{
diff --git a/arch/hexagon/include/asm/syscall.h b/arch/hexagon/include/asm/syscall.h
index f6e454f18038..1024a6548d78 100644
--- a/arch/hexagon/include/asm/syscall.h
+++ b/arch/hexagon/include/asm/syscall.h
@@ -33,6 +33,13 @@ static inline void syscall_get_arguments(struct task_struct *task,
memcpy(args, &(&regs->r00)[0], 6 * sizeof(args[0]));
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ memcpy(&(&regs->r00)[0], args, 6 * sizeof(args[0]));
+}
+
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
@@ -45,6 +52,13 @@ static inline long syscall_get_return_value(struct task_struct *task,
return regs->r00;
}

+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ regs->r00 = (long) error ?: val;
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_HEXAGON;
diff --git a/arch/loongarch/include/asm/syscall.h b/arch/loongarch/include/asm/syscall.h
index e286dc58476e..ff415b3c0a8e 100644
--- a/arch/loongarch/include/asm/syscall.h
+++ b/arch/loongarch/include/asm/syscall.h
@@ -61,6 +61,14 @@ static inline void syscall_get_arguments(struct task_struct *task,
memcpy(&args[1], &regs->regs[5], 5 * sizeof(long));
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ regs->orig_a0 = args[0];
+ memcpy(&regs->regs[5], &args[1], 5 * sizeof(long));
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_LOONGARCH64;
diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index b3f00ede8bb3..2dcc1d01b405 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -74,6 +74,23 @@ static inline void mips_get_syscall_arg(unsigned long *arg,
#endif
}

+static inline void mips_set_syscall_arg(unsigned long *arg,
+ struct task_struct *task, struct pt_regs *regs, unsigned int n)
+{
+#ifdef CONFIG_32BIT
+ switch (n) {
+ case 0: case 1: case 2: case 3:
+ regs->regs[4 + n] = *arg;
+ return;
+ case 4: case 5: case 6: case 7:
+ *arg = regs->pad0[n] = *arg;
+ return;
+ }
+#else
+ regs->regs[4 + n] = *arg;
+#endif
+}
+
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
@@ -120,6 +137,21 @@ static inline void syscall_get_arguments(struct task_struct *task,
mips_get_syscall_arg(args++, task, regs, i++);
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ unsigned int i = 0;
+ unsigned int n = 6;
+
+ /* O32 ABI syscall() */
+ if (mips_syscall_is_indirect(task, regs))
+ i++;
+
+ while (n--)
+ mips_set_syscall_arg(args++, task, regs, i++);
+}
+
extern const unsigned long sys_call_table[];
extern const unsigned long sys32_call_table[];
extern const unsigned long sysn32_call_table[];
diff --git a/arch/nios2/include/asm/syscall.h b/arch/nios2/include/asm/syscall.h
index fff52205fb65..526449edd768 100644
--- a/arch/nios2/include/asm/syscall.h
+++ b/arch/nios2/include/asm/syscall.h
@@ -58,6 +58,17 @@ static inline void syscall_get_arguments(struct task_struct *task,
*args = regs->r9;
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs, const unsigned long *args)
+{
+ regs->r4 = *args++;
+ regs->r5 = *args++;
+ regs->r6 = *args++;
+ regs->r7 = *args++;
+ regs->r8 = *args++;
+ regs->r9 = *args;
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_NIOS2;
diff --git a/arch/openrisc/include/asm/syscall.h b/arch/openrisc/include/asm/syscall.h
index 903ed882bdec..e6383be2a195 100644
--- a/arch/openrisc/include/asm/syscall.h
+++ b/arch/openrisc/include/asm/syscall.h
@@ -57,6 +57,13 @@ syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
memcpy(args, &regs->gpr[3], 6 * sizeof(args[0]));
}

+static inline void
+syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+ const unsigned long *args)
+{
+ memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_OPENRISC;
diff --git a/arch/parisc/include/asm/syscall.h b/arch/parisc/include/asm/syscall.h
index 00b127a5e09b..b146d0ae4c77 100644
--- a/arch/parisc/include/asm/syscall.h
+++ b/arch/parisc/include/asm/syscall.h
@@ -29,6 +29,18 @@ static inline void syscall_get_arguments(struct task_struct *tsk,
args[0] = regs->gr[26];
}

+static inline void syscall_set_arguments(struct task_struct *tsk,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ regs->gr[21] = args[5];
+ regs->gr[22] = args[4];
+ regs->gr[23] = args[3];
+ regs->gr[24] = args[2];
+ regs->gr[25] = args[1];
+ regs->gr[26] = args[0];
+}
+
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 422d7735ace6..521f279e6b33 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -114,6 +114,16 @@ static inline void syscall_get_arguments(struct task_struct *task,
}
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ memcpy(&regs->gpr[3], args, 6 * sizeof(args[0]));
+
+ /* Also copy the first argument into orig_gpr3 */
+ regs->orig_gpr3 = args[0];
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
if (is_tsk_32bit_task(task))
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 121fff429dce..8d389ba995c8 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -66,6 +66,15 @@ static inline void syscall_get_arguments(struct task_struct *task,
memcpy(args, &regs->a1, 5 * sizeof(args[0]));
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ regs->orig_a0 = args[0];
+ args++;
+ memcpy(&regs->a1, args, 5 * sizeof(regs->a1));
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
#ifdef CONFIG_64BIT
diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
index 27e3d804b311..b3dd883699e7 100644
--- a/arch/s390/include/asm/syscall.h
+++ b/arch/s390/include/asm/syscall.h
@@ -78,6 +78,18 @@ static inline void syscall_get_arguments(struct task_struct *task,
args[0] = regs->orig_gpr2 & mask;
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ unsigned int n = 6;
+
+ while (n-- > 0)
+ if (n > 0)
+ regs->gprs[2 + n] = args[n];
+ regs->orig_gpr2 = args[0];
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
diff --git a/arch/sh/include/asm/syscall_32.h b/arch/sh/include/asm/syscall_32.h
index d87738eebe30..cb51a7528384 100644
--- a/arch/sh/include/asm/syscall_32.h
+++ b/arch/sh/include/asm/syscall_32.h
@@ -57,6 +57,18 @@ static inline void syscall_get_arguments(struct task_struct *task,
args[0] = regs->regs[4];
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ regs->regs[1] = args[5];
+ regs->regs[0] = args[4];
+ regs->regs[7] = args[3];
+ regs->regs[6] = args[2];
+ regs->regs[5] = args[1];
+ regs->regs[4] = args[0];
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
int arch = AUDIT_ARCH_SH;
diff --git a/arch/sparc/include/asm/syscall.h b/arch/sparc/include/asm/syscall.h
index 20c109ac8cc9..62a5a78804c4 100644
--- a/arch/sparc/include/asm/syscall.h
+++ b/arch/sparc/include/asm/syscall.h
@@ -117,6 +117,16 @@ static inline void syscall_get_arguments(struct task_struct *task,
}
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ unsigned int i;
+
+ for (i = 0; i < 6; i++)
+ regs->u_regs[UREG_I0 + i] = args[i];
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
#if defined(CONFIG_SPARC64) && defined(CONFIG_COMPAT)
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
index 172b74143c4b..2984feb9d576 100644
--- a/arch/um/include/asm/syscall-generic.h
+++ b/arch/um/include/asm/syscall-generic.h
@@ -62,6 +62,20 @@ static inline void syscall_get_arguments(struct task_struct *task,
*args = UPT_SYSCALL_ARG6(r);
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ struct uml_pt_regs *r = &regs->regs;
+
+ UPT_SYSCALL_ARG1(r) = *args++;
+ UPT_SYSCALL_ARG2(r) = *args++;
+ UPT_SYSCALL_ARG3(r) = *args++;
+ UPT_SYSCALL_ARG4(r) = *args++;
+ UPT_SYSCALL_ARG5(r) = *args++;
+ UPT_SYSCALL_ARG6(r) = *args;
+}
+
/* See arch/x86/um/asm/syscall.h for syscall_get_arch() definition. */

#endif /* __UM_SYSCALL_GENERIC_H */
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index 7c488ff0c764..b9c249dd9e3d 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -90,6 +90,18 @@ static inline void syscall_get_arguments(struct task_struct *task,
args[5] = regs->bp;
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ regs->bx = args[0];
+ regs->cx = args[1];
+ regs->dx = args[2];
+ regs->si = args[3];
+ regs->di = args[4];
+ regs->bp = args[5];
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_I386;
@@ -121,6 +133,30 @@ static inline void syscall_get_arguments(struct task_struct *task,
}
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+# ifdef CONFIG_IA32_EMULATION
+ if (task->thread_info.status & TS_COMPAT) {
+ regs->bx = *args++;
+ regs->cx = *args++;
+ regs->dx = *args++;
+ regs->si = *args++;
+ regs->di = *args++;
+ regs->bp = *args;
+ } else
+# endif
+ {
+ regs->di = *args++;
+ regs->si = *args++;
+ regs->dx = *args++;
+ regs->r10 = *args++;
+ regs->r8 = *args++;
+ regs->r9 = *args;
+ }
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
/* x32 tasks should be considered AUDIT_ARCH_X86_64. */
diff --git a/arch/xtensa/include/asm/syscall.h b/arch/xtensa/include/asm/syscall.h
index 5ee974bf8330..f9a671cbf933 100644
--- a/arch/xtensa/include/asm/syscall.h
+++ b/arch/xtensa/include/asm/syscall.h
@@ -68,6 +68,17 @@ static inline void syscall_get_arguments(struct task_struct *task,
args[i] = regs->areg[reg[i]];
}

+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ const unsigned long *args)
+{
+ static const unsigned int reg[] = XTENSA_SYSCALL_ARGUMENT_REGS;
+ unsigned int i;
+
+ for (i = 0; i < 6; ++i)
+ regs->areg[reg[i]] = args[i];
+}
+
asmlinkage long xtensa_rt_sigreturn(void);
asmlinkage long xtensa_shmat(int, char __user *, int);
asmlinkage long xtensa_fadvise64_64(int, int,
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 5a80fe728dc8..0f7b9a493de7 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -117,6 +117,22 @@ void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
void syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
unsigned long *args);

+/**
+ * syscall_set_arguments - change system call parameter value
+ * @task: task of interest, must be in system call entry tracing
+ * @regs: task_pt_regs() of @task
+ * @args: array of argument values to store
+ *
+ * Changes 6 arguments to the system call.
+ * The first argument gets value @args[0], and so on.
+ *
+ * It's only valid to call this when @task is stopped for tracing on
+ * entry to a system call, due to %SYSCALL_WORK_SYSCALL_TRACE or
+ * %SYSCALL_WORK_SYSCALL_AUDIT.
+ */
+void syscall_set_arguments(struct task_struct *task, struct pt_regs *regs,
+ const unsigned long *args);
+
/**
* syscall_get_arch - return the AUDIT_ARCH for the current system call
* @task: task of interest, must be blocked