* [PATCH v3 3/6] syscall.h: introduce syscall_set_nr()
2025-01-28 9:14 [PATCH v3 0/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO API Dmitry V. Levin
@ 2025-01-28 9:16 ` Dmitry V. Levin
2025-01-28 15:13 ` Christophe Leroy
2025-01-29 18:51 ` [PATCH v3 0/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO API Oleg Nesterov
1 sibling, 1 reply; 5+ messages in thread
From: Dmitry V. Levin @ 2025-01-28 9:16 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Alexey Gladkov, Charlie Jenkins, Eugene Syromyatnikov,
Mike Frysinger, Renzo Davoli, Davide Berardi, strace-devel,
Vineet Gupta, Russell King, Catalin Marinas, Will Deacon,
Brian Cain, Huacai Chen, WANG Xuerui, Geert Uytterhoeven,
Michal Simek, Thomas Bogendoerfer, Dinh Nguyen, Jonas Bonn,
Stefan Kristiansson, Stafford Horne, James E.J. Bottomley,
Helge Deller, Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Naveen N Rao, Madhavan Srinivasan, Paul Walmsley, Palmer Dabbelt,
Albert Ou, Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, Yoshinori Sato, Rich Felker,
John Paul Adrian Glaubitz, David S. Miller, Andreas Larsson,
Richard Weinberger, Anton Ivanov, Johannes Berg, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Chris Zankel, Max Filippov, Arnd Bergmann, linux-snps-arc,
linux-kernel, linux-arm-kernel, linux-hexagon, loongarch,
linux-m68k, linux-mips, linux-openrisc, linux-parisc,
linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
linux-um, linux-arch
Similar to syscall_set_arguments() that complements
syscall_get_arguments(), introduce syscall_set_nr()
that complements syscall_get_nr().
syscall_set_nr() is going to be needed along with
syscall_set_arguments() on all HAVE_ARCH_TRACEHOOK
architectures to implement PTRACE_SET_SYSCALL_INFO API.
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 | 11 +++++++++++
arch/arm/include/asm/syscall.h | 24 ++++++++++++++++++++++++
arch/arm64/include/asm/syscall.h | 16 ++++++++++++++++
arch/hexagon/include/asm/syscall.h | 7 +++++++
arch/loongarch/include/asm/syscall.h | 7 +++++++
arch/m68k/include/asm/syscall.h | 7 +++++++
arch/microblaze/include/asm/syscall.h | 7 +++++++
arch/mips/include/asm/syscall.h | 14 ++++++++++++++
arch/nios2/include/asm/syscall.h | 5 +++++
arch/openrisc/include/asm/syscall.h | 6 ++++++
arch/parisc/include/asm/syscall.h | 7 +++++++
arch/powerpc/include/asm/syscall.h | 10 ++++++++++
arch/riscv/include/asm/syscall.h | 7 +++++++
arch/s390/include/asm/syscall.h | 12 ++++++++++++
arch/sh/include/asm/syscall_32.h | 12 ++++++++++++
arch/sparc/include/asm/syscall.h | 12 ++++++++++++
arch/um/include/asm/syscall-generic.h | 5 +++++
arch/x86/include/asm/syscall.h | 7 +++++++
arch/xtensa/include/asm/syscall.h | 7 +++++++
include/asm-generic/syscall.h | 14 ++++++++++++++
20 files changed, 197 insertions(+)
diff --git a/arch/arc/include/asm/syscall.h b/arch/arc/include/asm/syscall.h
index 89c1e1736356..728d625a10f1 100644
--- a/arch/arc/include/asm/syscall.h
+++ b/arch/arc/include/asm/syscall.h
@@ -23,6 +23,17 @@ syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return -1;
}
+static inline void
+syscall_set_nr(struct task_struct *task, struct pt_regs *regs, int nr)
+{
+ /*
+ * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
+ * the target task is stopped for tracing on entering syscall, so
+ * there is no need to have the same check syscall_get_nr() has.
+ */
+ regs->r8 = nr;
+}
+
static inline void
syscall_rollback(struct task_struct *task, struct pt_regs *regs)
{
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index 21927fa0ae2b..18b102a30741 100644
--- a/arch/arm/include/asm/syscall.h
+++ b/arch/arm/include/asm/syscall.h
@@ -68,6 +68,30 @@ static inline void syscall_set_return_value(struct task_struct *task,
regs->ARM_r0 = (long) error ? error : val;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ if (nr == -1) {
+ task_thread_info(task)->abi_syscall = -1;
+ /*
+ * When the syscall number is set to -1, the syscall will be
+ * skipped. In this case the syscall return value has to be
+ * set explicitly, otherwise the first syscall argument is
+ * returned as the syscall return value.
+ */
+ syscall_set_return_value(task, regs, -ENOSYS, 0);
+ return;
+ }
+ if ((IS_ENABLED(CONFIG_AEABI) && !IS_ENABLED(CONFIG_OABI_COMPAT))) {
+ task_thread_info(task)->abi_syscall = nr;
+ return;
+ }
+ task_thread_info(task)->abi_syscall =
+ (task_thread_info(task)->abi_syscall & ~__NR_SYSCALL_MASK) |
+ (nr & __NR_SYSCALL_MASK);
+}
+
#define SYSCALL_MAX_ARGS 7
static inline void syscall_get_arguments(struct task_struct *task,
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index 76020b66286b..712daa90e643 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -61,6 +61,22 @@ static inline void syscall_set_return_value(struct task_struct *task,
regs->regs[0] = val;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->syscallno = nr;
+ if (nr == -1) {
+ /*
+ * When the syscall number is set to -1, the syscall will be
+ * skipped. In this case the syscall return value has to be
+ * set explicitly, otherwise the first syscall argument is
+ * returned as the syscall return value.
+ */
+ syscall_set_return_value(task, regs, -ENOSYS, 0);
+ }
+}
+
#define SYSCALL_MAX_ARGS 6
static inline void syscall_get_arguments(struct task_struct *task,
diff --git a/arch/hexagon/include/asm/syscall.h b/arch/hexagon/include/asm/syscall.h
index 1024a6548d78..70637261817a 100644
--- a/arch/hexagon/include/asm/syscall.h
+++ b/arch/hexagon/include/asm/syscall.h
@@ -26,6 +26,13 @@ static inline long syscall_get_nr(struct task_struct *task,
return regs->r06;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->r06 = nr;
+}
+
static inline void syscall_get_arguments(struct task_struct *task,
struct pt_regs *regs,
unsigned long *args)
diff --git a/arch/loongarch/include/asm/syscall.h b/arch/loongarch/include/asm/syscall.h
index ff415b3c0a8e..81d2733f7b94 100644
--- a/arch/loongarch/include/asm/syscall.h
+++ b/arch/loongarch/include/asm/syscall.h
@@ -26,6 +26,13 @@ static inline long syscall_get_nr(struct task_struct *task,
return regs->regs[11];
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->regs[11] = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/m68k/include/asm/syscall.h b/arch/m68k/include/asm/syscall.h
index d1453e850cdd..bf84b160c2eb 100644
--- a/arch/m68k/include/asm/syscall.h
+++ b/arch/m68k/include/asm/syscall.h
@@ -14,6 +14,13 @@ static inline int syscall_get_nr(struct task_struct *task,
return regs->orig_d0;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->orig_d0 = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/microblaze/include/asm/syscall.h b/arch/microblaze/include/asm/syscall.h
index 5eb3f624cc59..b5b6b91fae3e 100644
--- a/arch/microblaze/include/asm/syscall.h
+++ b/arch/microblaze/include/asm/syscall.h
@@ -14,6 +14,13 @@ static inline long syscall_get_nr(struct task_struct *task,
return regs->r12;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->r12 = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/mips/include/asm/syscall.h b/arch/mips/include/asm/syscall.h
index 2dcc1d01b405..1cd25306cc13 100644
--- a/arch/mips/include/asm/syscall.h
+++ b/arch/mips/include/asm/syscall.h
@@ -41,6 +41,20 @@ static inline long syscall_get_nr(struct task_struct *task,
return task_thread_info(task)->syscall;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ /*
+ * New syscall number has to be assigned to regs[2] because
+ * syscall_trace_entry() loads it from there unconditionally.
+ *
+ * Consequently, if the syscall was indirect and nr != __NR_syscall,
+ * then after this assignment the syscall will cease to be indirect.
+ */
+ task_thread_info(task)->syscall = regs->regs[2] = nr;
+}
+
static inline void mips_syscall_update_nr(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/nios2/include/asm/syscall.h b/arch/nios2/include/asm/syscall.h
index 526449edd768..8e3eb1d689bb 100644
--- a/arch/nios2/include/asm/syscall.h
+++ b/arch/nios2/include/asm/syscall.h
@@ -15,6 +15,11 @@ static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return regs->r2;
}
+static inline void syscall_set_nr(struct task_struct *task, struct pt_regs *regs, int nr)
+{
+ regs->r2 = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/openrisc/include/asm/syscall.h b/arch/openrisc/include/asm/syscall.h
index e6383be2a195..5e037d9659c5 100644
--- a/arch/openrisc/include/asm/syscall.h
+++ b/arch/openrisc/include/asm/syscall.h
@@ -25,6 +25,12 @@ syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return regs->orig_gpr11;
}
+static inline void
+syscall_set_nr(struct task_struct *task, struct pt_regs *regs, int nr)
+{
+ regs->orig_gpr11 = nr;
+}
+
static inline void
syscall_rollback(struct task_struct *task, struct pt_regs *regs)
{
diff --git a/arch/parisc/include/asm/syscall.h b/arch/parisc/include/asm/syscall.h
index b146d0ae4c77..c11222798ab2 100644
--- a/arch/parisc/include/asm/syscall.h
+++ b/arch/parisc/include/asm/syscall.h
@@ -17,6 +17,13 @@ static inline long syscall_get_nr(struct task_struct *tsk,
return regs->gr[20];
}
+static inline void syscall_set_nr(struct task_struct *tsk,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->gr[20] = nr;
+}
+
static inline void syscall_get_arguments(struct task_struct *tsk,
struct pt_regs *regs,
unsigned long *args)
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 521f279e6b33..7505dcfed247 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -39,6 +39,16 @@ static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return -1;
}
+static inline void syscall_set_nr(struct task_struct *task, struct pt_regs *regs, int nr)
+{
+ /*
+ * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
+ * the target task is stopped for tracing on entering syscall, so
+ * there is no need to have the same check syscall_get_nr() has.
+ */
+ regs->gpr[0] = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/riscv/include/asm/syscall.h b/arch/riscv/include/asm/syscall.h
index 8d389ba995c8..a5281cdf2b10 100644
--- a/arch/riscv/include/asm/syscall.h
+++ b/arch/riscv/include/asm/syscall.h
@@ -30,6 +30,13 @@ static inline int syscall_get_nr(struct task_struct *task,
return regs->a7;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->a7 = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h
index b3dd883699e7..12cd0c60c07b 100644
--- a/arch/s390/include/asm/syscall.h
+++ b/arch/s390/include/asm/syscall.h
@@ -24,6 +24,18 @@ static inline long syscall_get_nr(struct task_struct *task,
(regs->int_code & 0xffff) : -1;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ /*
+ * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
+ * the target task is stopped for tracing on entering syscall, so
+ * there is no need to have the same check syscall_get_nr() has.
+ */
+ regs->int_code = (regs->int_code & ~0xffff) | (nr & 0xffff);
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/sh/include/asm/syscall_32.h b/arch/sh/include/asm/syscall_32.h
index cb51a7528384..7027d87d901d 100644
--- a/arch/sh/include/asm/syscall_32.h
+++ b/arch/sh/include/asm/syscall_32.h
@@ -15,6 +15,18 @@ static inline long syscall_get_nr(struct task_struct *task,
return (regs->tra >= 0) ? regs->regs[3] : -1L;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ /*
+ * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
+ * the target task is stopped for tracing on entering syscall, so
+ * there is no need to have the same check syscall_get_nr() has.
+ */
+ regs->regs[3] = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/sparc/include/asm/syscall.h b/arch/sparc/include/asm/syscall.h
index 62a5a78804c4..b0233924d323 100644
--- a/arch/sparc/include/asm/syscall.h
+++ b/arch/sparc/include/asm/syscall.h
@@ -25,6 +25,18 @@ static inline long syscall_get_nr(struct task_struct *task,
return (syscall_p ? regs->u_regs[UREG_G1] : -1L);
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ /*
+ * Unlike syscall_get_nr(), syscall_set_nr() can be called only when
+ * the target task is stopped for tracing on entering syscall, so
+ * there is no need to have the same check syscall_get_nr() has.
+ */
+ regs->u_regs[UREG_G1] = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/um/include/asm/syscall-generic.h b/arch/um/include/asm/syscall-generic.h
index 2984feb9d576..bcd73bcfe577 100644
--- a/arch/um/include/asm/syscall-generic.h
+++ b/arch/um/include/asm/syscall-generic.h
@@ -21,6 +21,11 @@ static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return PT_REGS_SYSCALL_NR(regs);
}
+static inline void syscall_set_nr(struct task_struct *task, struct pt_regs *regs, int nr)
+{
+ PT_REGS_SYSCALL_NR(regs) = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index b9c249dd9e3d..c10dbb74cd00 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -38,6 +38,13 @@ static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
return regs->orig_ax;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->orig_ax = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/arch/xtensa/include/asm/syscall.h b/arch/xtensa/include/asm/syscall.h
index f9a671cbf933..7db3b489c8ad 100644
--- a/arch/xtensa/include/asm/syscall.h
+++ b/arch/xtensa/include/asm/syscall.h
@@ -28,6 +28,13 @@ static inline long syscall_get_nr(struct task_struct *task,
return regs->syscall;
}
+static inline void syscall_set_nr(struct task_struct *task,
+ struct pt_regs *regs,
+ int nr)
+{
+ regs->syscall = nr;
+}
+
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
diff --git a/include/asm-generic/syscall.h b/include/asm-generic/syscall.h
index 0f7b9a493de7..e33fd4e783c1 100644
--- a/include/asm-generic/syscall.h
+++ b/include/asm-generic/syscall.h
@@ -37,6 +37,20 @@ struct pt_regs;
*/
int syscall_get_nr(struct task_struct *task, struct pt_regs *regs);
+/**
+ * syscall_set_nr - change the system call a task is executing
+ * @task: task of interest, must be blocked
+ * @regs: task_pt_regs() of @task
+ * @nr: system call number
+ *
+ * Changes the system call number @task is about to execute.
+ *
+ * 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_nr(struct task_struct *task, struct pt_regs *regs, int nr);
+
/**
* syscall_rollback - roll back registers after an aborted system call
* @task: task of interest, must be in system call exit tracing
--
ldv
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v3 0/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO API
2025-01-28 9:14 [PATCH v3 0/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO API Dmitry V. Levin
2025-01-28 9:16 ` [PATCH v3 3/6] syscall.h: introduce syscall_set_nr() Dmitry V. Levin
@ 2025-01-29 18:51 ` Oleg Nesterov
1 sibling, 0 replies; 5+ messages in thread
From: Oleg Nesterov @ 2025-01-29 18:51 UTC (permalink / raw)
To: Dmitry V. Levin
Cc: Alexey Gladkov, Charlie Jenkins, Eugene Syromyatnikov,
Mike Frysinger, Renzo Davoli, Davide Berardi, strace-devel,
Vineet Gupta, Russell King, Will Deacon, Guo Ren, Brian Cain,
Huacai Chen, WANG Xuerui, Geert Uytterhoeven, Michal Simek,
Thomas Bogendoerfer, Dinh Nguyen, Jonas Bonn, Stefan Kristiansson,
Stafford Horne, James E.J. Bottomley, Helge Deller,
Michael Ellerman, Nicholas Piggin, Christophe Leroy, Naveen N Rao,
Madhavan Srinivasan, Paul Walmsley, Palmer Dabbelt, Albert Ou,
Heiko Carstens, Vasily Gorbik, Alexander Gordeev,
Christian Borntraeger, Sven Schnelle, Yoshinori Sato, Rich Felker,
John Paul Adrian Glaubitz, David S. Miller, Andreas Larsson,
Richard Weinberger, Anton Ivanov, Johannes Berg, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, x86, H. Peter Anvin,
Chris Zankel, Max Filippov, Arnd Bergmann, Shuah Khan,
linux-snps-arc, linux-kernel, linux-arm-kernel, linux-csky,
linux-hexagon, loongarch, linux-m68k, linux-mips, linux-openrisc,
linux-parisc, linuxppc-dev, linux-riscv, linux-s390, linux-sh,
sparclinux, linux-um, linux-arch, linux-kselftest, linux-api
On 01/28, Dmitry V. Levin wrote:
>
> * ptrace: Add explicit padding to the end of struct ptrace_syscall_info,
> simplify obtaining of user ptrace_syscall_info,
> do not introduce PTRACE_SYSCALL_INFO_SIZE_VER0
> * ptrace: Change the return type of ptrace_set_syscall_info_* functions
> from "unsigned long" to "int"
> * ptrace: Add -ERANGE check to ptrace_set_syscall_info_exit,
> add comments to -ERANGE checks
> * ptrace: Update comments about supported syscall stops
> * selftests: Extend set_syscall_info test, fix for mips n32
Again, I can't review 1-3, I know nothing about the non-x86 architectures.
As for 4-6, feel free to add
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread