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authorNicholas Piggin <npiggin@gmail.com>2021-05-20 14:19:31 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2021-05-20 17:58:56 +0300
commitd72500f992849d31ebae8f821a023660ddd0dcc2 (patch)
treeba13c3f0cf481d3653836f19769fe685021c9826 /arch/powerpc
parent5665bc35c1ed917ac8fd06cb651317bb47a65b10 (diff)
downloadlinux-d72500f992849d31ebae8f821a023660ddd0dcc2.tar.xz
powerpc/64s/syscall: Fix ptrace syscall info with scv syscalls
The scv implementation missed updating syscall return value and error value get/set functions to deal with the changed register ABI. This broke ptrace PTRACE_GET_SYSCALL_INFO as well as some kernel auditing and tracing functions. Fix. tools/testing/selftests/ptrace/get_syscall_info now passes when scv is used. Fixes: 7fa95f9adaee ("powerpc/64s: system call support for scv/rfscv instructions") Cc: stable@vger.kernel.org # v5.9+ Reported-by: "Dmitry V. Levin" <ldv@altlinux.org> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Dmitry V. Levin <ldv@altlinux.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210520111931.2597127-2-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/include/asm/ptrace.h45
-rw-r--r--arch/powerpc/include/asm/syscall.h42
2 files changed, 52 insertions, 35 deletions
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 9c9ab2746168..b476a685f066 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -19,6 +19,7 @@
#ifndef _ASM_POWERPC_PTRACE_H
#define _ASM_POWERPC_PTRACE_H
+#include <linux/err.h>
#include <uapi/asm/ptrace.h>
#include <asm/asm-const.h>
@@ -152,25 +153,6 @@ extern unsigned long profile_pc(struct pt_regs *regs);
long do_syscall_trace_enter(struct pt_regs *regs);
void do_syscall_trace_leave(struct pt_regs *regs);
-#define kernel_stack_pointer(regs) ((regs)->gpr[1])
-static inline int is_syscall_success(struct pt_regs *regs)
-{
- return !(regs->ccr & 0x10000000);
-}
-
-static inline long regs_return_value(struct pt_regs *regs)
-{
- if (is_syscall_success(regs))
- return regs->gpr[3];
- else
- return -regs->gpr[3];
-}
-
-static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
-{
- regs->gpr[3] = rc;
-}
-
#ifdef __powerpc64__
#define user_mode(regs) ((((regs)->msr) >> MSR_PR_LG) & 0x1)
#else
@@ -235,6 +217,31 @@ static __always_inline void set_trap_norestart(struct pt_regs *regs)
regs->trap |= 0x1;
}
+#define kernel_stack_pointer(regs) ((regs)->gpr[1])
+static inline int is_syscall_success(struct pt_regs *regs)
+{
+ if (trap_is_scv(regs))
+ return !IS_ERR_VALUE((unsigned long)regs->gpr[3]);
+ else
+ return !(regs->ccr & 0x10000000);
+}
+
+static inline long regs_return_value(struct pt_regs *regs)
+{
+ if (trap_is_scv(regs))
+ return regs->gpr[3];
+
+ if (is_syscall_success(regs))
+ return regs->gpr[3];
+ else
+ return -regs->gpr[3];
+}
+
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+{
+ regs->gpr[3] = rc;
+}
+
#define arch_has_single_step() (1)
#define arch_has_block_step() (true)
#define ARCH_HAS_USER_SINGLE_STEP_REPORT
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index fd1b518eed17..ba0f88f3a30d 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -41,11 +41,17 @@ static inline void syscall_rollback(struct task_struct *task,
static inline long syscall_get_error(struct task_struct *task,
struct pt_regs *regs)
{
- /*
- * If the system call failed,
- * regs->gpr[3] contains a positive ERRORCODE.
- */
- return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
+ if (trap_is_scv(regs)) {
+ unsigned long error = regs->gpr[3];
+
+ return IS_ERR_VALUE(error) ? error : 0;
+ } else {
+ /*
+ * If the system call failed,
+ * regs->gpr[3] contains a positive ERRORCODE.
+ */
+ return (regs->ccr & 0x10000000UL) ? -regs->gpr[3] : 0;
+ }
}
static inline long syscall_get_return_value(struct task_struct *task,
@@ -58,18 +64,22 @@ static inline void syscall_set_return_value(struct task_struct *task,
struct pt_regs *regs,
int error, long val)
{
- /*
- * In the general case it's not obvious that we must deal with CCR
- * here, as the syscall exit path will also do that for us. However
- * there are some places, eg. the signal code, which check ccr to
- * decide if the value in r3 is actually an error.
- */
- if (error) {
- regs->ccr |= 0x10000000L;
- regs->gpr[3] = error;
+ if (trap_is_scv(regs)) {
+ regs->gpr[3] = (long) error ?: val;
} else {
- regs->ccr &= ~0x10000000L;
- regs->gpr[3] = val;
+ /*
+ * In the general case it's not obvious that we must deal with
+ * CCR here, as the syscall exit path will also do that for us.
+ * However there are some places, eg. the signal code, which
+ * check ccr to decide if the value in r3 is actually an error.
+ */
+ if (error) {
+ regs->ccr |= 0x10000000L;
+ regs->gpr[3] = error;
+ } else {
+ regs->ccr &= ~0x10000000L;
+ regs->gpr[3] = val;
+ }
}
}