Hi Zachary, On Thu, Oct 06, 2022 at 04:58:10PM +0100, Zachary Leaf wrote:
On 05/10/2022 16:08, Beata Michalska wrote:
The alterations around the syscall framework made to enable support for capabilities, did spin the syscalls tracing out of control and broke number
broke "a" number
Noted.
of things on the way. In order to get it back in line (eventually), make necessary adjustments to SYSCALL_METADATA and provide dedicated implementation for arch_syscall_addr.
SYSCALL_METADATA gets split into double-phased set-up, allowing archs to redefine how the arguments for the actual metadata handler macro are being arranged. On a side note, that those unify (at the surface at least) the order of the arguments used by syscall framework.
s/that those // ?
That one was supposed to be 'does' ...
Does switching the args fix anything here or it's just to align with the order in __SYSCALL_DEFINEx?
This is actually the main fix - the SYSCALL_METADATA originally gets the arguments being swapped, which in othe case of arm64 is a problem as the syscall name is bing extended by the type of return value so the SYSCALL_DEFINE with (x, name ... ) will eventually get (x, name, ret_type, .....) but as SYSCALL_METADATA gets the order flipped, instead of getting (name, x ...) it will get (name, ret_type, x...) which causes all the problems. So what we are doing here is overriding SYSCALL_METADATA with original order of arguments, dropping the ret_type, and then flipping the order to feed that in into (what is now) __SYSCALL_METADATA.
--- BR B.
Fixes: bb3fbc44e783 ("arm64/syscalls: Allow syscalls to return capabilities") Signed-off-by: Beata Michalska beata.michalska@arm.com
arch/arm64/include/asm/ftrace.h | 4 ++++ arch/arm64/include/asm/syscall_wrapper.h | 9 ++++++--- arch/arm64/kernel/syscall.c | 12 ++++++++++++ arch/s390/include/asm/syscall_wrapper.h | 6 +++--- arch/x86/include/asm/syscall_wrapper.h | 2 +- include/linux/syscalls.h | 24 +++++++++++++++--------- 6 files changed, 41 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 665373f441e1..0e277c532344 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -102,6 +102,10 @@ static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) return is_32bit_compat_task(); } +#ifdef CONFIG_CHERI_PURECAP_UABI +#define ARCH_HAS_SYSCALL_ADDR +#endif
#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME static inline bool arch_syscall_match_sym_name(const char *sym, diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h index b823aee59b6c..0ebee1ea0661 100644 --- a/arch/arm64/include/asm/syscall_wrapper.h +++ b/arch/arm64/include/asm/syscall_wrapper.h @@ -68,7 +68,7 @@ struct pt_regs; } #define __SYSCALL_DEFINE0(sname, ret_type) \
- SYSCALL_METADATA(sname, 0); \
- SYSCALL_METADATA(0, sname,); \ asmlinkage ret_type __arm64_sys##sname(const struct pt_regs *__unused); \ ALLOW_ERROR_INJECTION(__arm64_sys##sname, ERRNO); \ asmlinkage ret_type __arm64_compatentry_sys##sname(const struct pt_regs *__unused)\
@@ -94,7 +94,7 @@ struct pt_regs; #define __ARM64_SYS_STUBx(x, name, ...) #define __SYSCALL_DEFINE0(sname, ret_type) \
- SYSCALL_METADATA(sname, 0); \
- SYSCALL_METADATA(0, sname,); \ asmlinkage ret_type __arm64_sys##sname(const struct pt_regs *__unused); \ ALLOW_ERROR_INJECTION(__arm64_sys##sname, ERRNO); \ asmlinkage ret_type __arm64_sys##sname(const struct pt_regs *__unused)
@@ -141,7 +141,10 @@ struct pt_regs; #define __retptr__(name) name, _PTR #define __SYSCALL_ANNOTATE(name, ret_type) name, __SYSCALL_RET_T##ret_type #define SYSCALL_PREP(name, ...) __SYSCALL_ANNOTATE(_##name, __VA_ARGS__)
+#ifdef CONFIG_FTRACE_SYSCALLS +#define SYSCALL_METADATA(x, name, ret_type, ...) \
- __SYSCALL_METADATA(name, x, __VA_ARGS__)
+#endif /*
- Some syscalls with no parameters return valid capabilities, so __SYSCALL_DEFINE0
- is added to handle such cases.
diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index a0e91ea7b74b..4942fcb4d299 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -105,6 +105,18 @@ static inline bool has_syscall_work(unsigned long flags) return unlikely(flags & _TIF_SYSCALL_WORK); } +#if defined(CONFIG_CHERI_PURECAP_UABI) && defined(CONFIG_FTRACE_SYSCALLS) +unsigned long __init arch_syscall_addr(int nr) +{
- /*
* In this particular case, it makes no difference,* which member of the syscall_entry_t instance is being* provided - the address is all that matters here*/- return (unsigned long)sys_call_table[nr].syscall_fn;
+} +#endif
int syscall_trace_enter(struct pt_regs *regs); void syscall_trace_exit(struct pt_regs *regs); diff --git a/arch/s390/include/asm/syscall_wrapper.h b/arch/s390/include/asm/syscall_wrapper.h index fde7e6b1df48..dee9c319734d 100644 --- a/arch/s390/include/asm/syscall_wrapper.h +++ b/arch/s390/include/asm/syscall_wrapper.h @@ -72,13 +72,13 @@
- named __s390x_sys_*()
*/ #define COMPAT_SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- SYSCALL_METADATA(0, _##sname); \ long __s390_compat_sys_##sname(void); \ ALLOW_ERROR_INJECTION(__s390_compat_sys_##sname, ERRNO); \ long __s390_compat_sys_##sname(void)
#define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- SYSCALL_METADATA(0, _##sname); \ long __s390x_sys_##sname(void); \ ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \ long __s390_sys_##sname(void) \
@@ -129,7 +129,7 @@ #define __S390_SYS_STUBx(x, fullname, name, ...) #define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- SYSCALL_METADATA(0, _##sname); \ long __s390x_sys_##sname(void); \ ALLOW_ERROR_INJECTION(__s390x_sys_##sname, ERRNO); \ long __s390x_sys_##sname(void)
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h index 59358d1bf880..c39adc4810f0 100644 --- a/arch/x86/include/asm/syscall_wrapper.h +++ b/arch/x86/include/asm/syscall_wrapper.h @@ -247,7 +247,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
- macros to work correctly.
*/ #define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- SYSCALL_METADATA(0, _##sname); \ static long __do_sys_##sname(const struct pt_regs *__unused); \ __X64_SYS_STUB0(sname) \ __IA32_SYS_STUB0(sname) \
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 8a6f561ce1de..c82cecc50675 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -193,12 +193,12 @@ extern struct trace_event_functions exit_syscall_print_funcs; __section("_ftrace_events") \ *__event_exit_##sname = &event_exit_##sname; -#define SYSCALL_METADATA(sname, nb, ...) \
- static const char *types_##sname[] = { \
__MAP(nb,__SC_STR_TDECL,__VA_ARGS__) \- }; \
- static const char *args_##sname[] = { \
__MAP(nb,__SC_STR_ADECL,__VA_ARGS__) \+#define __SYSCALL_METADATA(sname, nb, ...) \
- static const char *types_##sname[] = { \
__MAP(nb,__SC_STR_TDECL,__VA_ARGS__) \- }; \
- static const char *args_##sname[] = { \
__MAP(nb,__SC_STR_ADECL,__VA_ARGS__) \@@ -224,7 +224,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) } #else -#define SYSCALL_METADATA(sname, nb, ...) +#define __SYSCALL_METADATA(sname, nb, ...) static inline int is_syscall_trace_event(struct trace_event_call *tp_event) { @@ -232,6 +232,12 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) } #endif +#ifndef SYSCALL_METADATA +#define SYSCALL_METADATA(nb, sname, ...) \
- __SYSCALL_METADATA(sname, nb, __VA_ARGS__)
+#endif
#ifndef __retptr__ #define __retptr__(name) name #undef SYSCALL_PREP @@ -240,7 +246,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) #ifndef SYSCALL_DEFINE0 #define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- SYSCALL_METADATA(0, _##sname); \ asmlinkage long sys_##sname(void); \ ALLOW_ERROR_INJECTION(sys_##sname, ERRNO); \ asmlinkage long sys_##sname(void)
@@ -256,7 +262,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event) #define SYSCALL_DEFINE_MAXARGS 6 #define SYSCALL_DEFINEx(x, sname, ...) \
- SYSCALL_METADATA(sname, x, __VA_ARGS__) \
- SYSCALL_METADATA(x, sname, __VA_ARGS__) \ __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
#define __PROTECT(...) asmlinkage_protect(__VA_ARGS__)
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