From: Nicholas Piggin npiggin@gmail.com
commit d72500f992849d31ebae8f821a023660ddd0dcc2 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/include/asm/ptrace.h | 45 +++++++++++++++++++++---------------- arch/powerpc/include/asm/syscall.h | 42 +++++++++++++++++++++------------- 2 files changed, 52 insertions(+), 35 deletions(-)
--- 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 p 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 @@ -252,6 +234,31 @@ static inline void set_trap_norestart(st regs->trap |= 0x10; }
+#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 --- a/arch/powerpc/include/asm/syscall.h +++ b/arch/powerpc/include/asm/syscall.h @@ -41,11 +41,17 @@ static inline void syscall_rollback(stru 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_va 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; + } } }