[PATCH 1/6] Revert "arch: remove unused function syscall_set_arguments()"

Dmitry V. Levin
2025-01-07T23:04:01Z

syscall_set_arguments() is going to be needed to implement
PTRACE_SET_SYSCALL_INFO API.

This is a partial revert: on a few architectures syscall_set_arguments()
implementations were buggy, so instead of adding them here and applying
fixes on top, cleaner implementations are coming in follow-up commits.

This reverts commit 7962c2eddbfe7cce879acb06f9b4f205789e57b7.

Signed-off-by: Dmitry V. Levin <ldv@strace.io>
---
arch/nios2/include/asm/syscall.h | 11 ++++++++
arch/openrisc/include/asm/syscall.h | 7 ++++++
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 ++++++++++++
11 files changed, 148 insertions(+)

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/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 3dd36c5e334a..b2715448a660 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -110,6 +110,16 @@ 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

--
ldv