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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/include/asm/syscall_wrapper.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/include/asm/syscall_wrapper.h')
-rw-r--r--arch/x86/include/asm/syscall_wrapper.h290
1 files changed, 290 insertions, 0 deletions
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
new file mode 100644
index 000000000..e3323a9dc
--- /dev/null
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -0,0 +1,290 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * syscall_wrapper.h - x86 specific wrappers to syscall definitions
+ */
+
+#ifndef _ASM_X86_SYSCALL_WRAPPER_H
+#define _ASM_X86_SYSCALL_WRAPPER_H
+
+#include <asm/ptrace.h>
+
+extern long __x64_sys_ni_syscall(const struct pt_regs *regs);
+extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
+
+/*
+ * Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes
+ * struct pt_regs *regs as the only argument of the syscall stub(s) named as:
+ * __x64_sys_*() - 64-bit native syscall
+ * __ia32_sys_*() - 32-bit native syscall or common compat syscall
+ * __ia32_compat_sys_*() - 32-bit compat syscall
+ * __x64_compat_sys_*() - 64-bit X32 compat syscall
+ *
+ * The registers are decoded according to the ABI:
+ * 64-bit: RDI, RSI, RDX, R10, R8, R9
+ * 32-bit: EBX, ECX, EDX, ESI, EDI, EBP
+ *
+ * The stub then passes the decoded arguments to the __se_sys_*() wrapper to
+ * perform sign-extension (omitted for zero-argument syscalls). Finally the
+ * arguments are passed to the __do_sys_*() function which is the actual
+ * syscall. These wrappers are marked as inline so the compiler can optimize
+ * the functions where appropriate.
+ *
+ * Example assembly (slightly re-ordered for better readability):
+ *
+ * <__x64_sys_recv>: <-- syscall with 4 parameters
+ * callq <__fentry__>
+ *
+ * mov 0x70(%rdi),%rdi <-- decode regs->di
+ * mov 0x68(%rdi),%rsi <-- decode regs->si
+ * mov 0x60(%rdi),%rdx <-- decode regs->dx
+ * mov 0x38(%rdi),%rcx <-- decode regs->r10
+ *
+ * xor %r9d,%r9d <-- clear %r9
+ * xor %r8d,%r8d <-- clear %r8
+ *
+ * callq __sys_recvfrom <-- do the actual work in __sys_recvfrom()
+ * which takes 6 arguments
+ *
+ * cltq <-- extend return value to 64-bit
+ * retq <-- return
+ *
+ * This approach avoids leaking random user-provided register content down
+ * the call chain.
+ */
+
+/* Mapping of registers to parameters for syscalls on x86-64 and x32 */
+#define SC_X86_64_REGS_TO_ARGS(x, ...) \
+ __MAP(x,__SC_ARGS \
+ ,,regs->di,,regs->si,,regs->dx \
+ ,,regs->r10,,regs->r8,,regs->r9) \
+
+
+/* SYSCALL_PT_ARGS is Adapted from s390x */
+#define SYSCALL_PT_ARG6(m, t1, t2, t3, t4, t5, t6) \
+ SYSCALL_PT_ARG5(m, t1, t2, t3, t4, t5), m(t6, (regs->bp))
+#define SYSCALL_PT_ARG5(m, t1, t2, t3, t4, t5) \
+ SYSCALL_PT_ARG4(m, t1, t2, t3, t4), m(t5, (regs->di))
+#define SYSCALL_PT_ARG4(m, t1, t2, t3, t4) \
+ SYSCALL_PT_ARG3(m, t1, t2, t3), m(t4, (regs->si))
+#define SYSCALL_PT_ARG3(m, t1, t2, t3) \
+ SYSCALL_PT_ARG2(m, t1, t2), m(t3, (regs->dx))
+#define SYSCALL_PT_ARG2(m, t1, t2) \
+ SYSCALL_PT_ARG1(m, t1), m(t2, (regs->cx))
+#define SYSCALL_PT_ARG1(m, t1) m(t1, (regs->bx))
+#define SYSCALL_PT_ARGS(x, ...) SYSCALL_PT_ARG##x(__VA_ARGS__)
+
+#define __SC_COMPAT_CAST(t, a) \
+ (__typeof(__builtin_choose_expr(__TYPE_IS_L(t), 0, 0U))) \
+ (unsigned int)a
+
+/* Mapping of registers to parameters for syscalls on i386 */
+#define SC_IA32_REGS_TO_ARGS(x, ...) \
+ SYSCALL_PT_ARGS(x, __SC_COMPAT_CAST, \
+ __MAP(x, __SC_TYPE, __VA_ARGS__)) \
+
+#define __SYS_STUB0(abi, name) \
+ long __##abi##_##name(const struct pt_regs *regs); \
+ ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
+ long __##abi##_##name(const struct pt_regs *regs) \
+ __alias(__do_##name);
+
+#define __SYS_STUBx(abi, name, ...) \
+ long __##abi##_##name(const struct pt_regs *regs); \
+ ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
+ long __##abi##_##name(const struct pt_regs *regs) \
+ { \
+ return __se_##name(__VA_ARGS__); \
+ }
+
+#define __COND_SYSCALL(abi, name) \
+ __weak long __##abi##_##name(const struct pt_regs *__unused); \
+ __weak long __##abi##_##name(const struct pt_regs *__unused) \
+ { \
+ return sys_ni_syscall(); \
+ }
+
+#define __SYS_NI(abi, name) \
+ SYSCALL_ALIAS(__##abi##_##name, sys_ni_posix_timers);
+
+#ifdef CONFIG_X86_64
+#define __X64_SYS_STUB0(name) \
+ __SYS_STUB0(x64, sys_##name)
+
+#define __X64_SYS_STUBx(x, name, ...) \
+ __SYS_STUBx(x64, sys##name, \
+ SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __X64_COND_SYSCALL(name) \
+ __COND_SYSCALL(x64, sys_##name)
+
+#define __X64_SYS_NI(name) \
+ __SYS_NI(x64, sys_##name)
+#else /* CONFIG_X86_64 */
+#define __X64_SYS_STUB0(name)
+#define __X64_SYS_STUBx(x, name, ...)
+#define __X64_COND_SYSCALL(name)
+#define __X64_SYS_NI(name)
+#endif /* CONFIG_X86_64 */
+
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
+#define __IA32_SYS_STUB0(name) \
+ __SYS_STUB0(ia32, sys_##name)
+
+#define __IA32_SYS_STUBx(x, name, ...) \
+ __SYS_STUBx(ia32, sys##name, \
+ SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __IA32_COND_SYSCALL(name) \
+ __COND_SYSCALL(ia32, sys_##name)
+
+#define __IA32_SYS_NI(name) \
+ __SYS_NI(ia32, sys_##name)
+#else /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+#define __IA32_SYS_STUB0(name)
+#define __IA32_SYS_STUBx(x, name, ...)
+#define __IA32_COND_SYSCALL(name)
+#define __IA32_SYS_NI(name)
+#endif /* CONFIG_X86_32 || CONFIG_IA32_EMULATION */
+
+#ifdef CONFIG_IA32_EMULATION
+/*
+ * For IA32 emulation, we need to handle "compat" syscalls *and* create
+ * additional wrappers (aptly named __ia32_sys_xyzzy) which decode the
+ * ia32 regs in the proper order for shared or "common" syscalls. As some
+ * syscalls may not be implemented, we need to expand COND_SYSCALL in
+ * kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this
+ * case as well.
+ */
+#define __IA32_COMPAT_SYS_STUB0(name) \
+ __SYS_STUB0(ia32, compat_sys_##name)
+
+#define __IA32_COMPAT_SYS_STUBx(x, name, ...) \
+ __SYS_STUBx(ia32, compat_sys##name, \
+ SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __IA32_COMPAT_COND_SYSCALL(name) \
+ __COND_SYSCALL(ia32, compat_sys_##name)
+
+#define __IA32_COMPAT_SYS_NI(name) \
+ __SYS_NI(ia32, compat_sys_##name)
+
+#else /* CONFIG_IA32_EMULATION */
+#define __IA32_COMPAT_SYS_STUB0(name)
+#define __IA32_COMPAT_SYS_STUBx(x, name, ...)
+#define __IA32_COMPAT_COND_SYSCALL(name)
+#define __IA32_COMPAT_SYS_NI(name)
+#endif /* CONFIG_IA32_EMULATION */
+
+
+#ifdef CONFIG_X86_X32_ABI
+/*
+ * For the x32 ABI, we need to create a stub for compat_sys_*() which is aware
+ * of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
+ * with x86_64 obviously do not need such care.
+ */
+#define __X32_COMPAT_SYS_STUB0(name) \
+ __SYS_STUB0(x64, compat_sys_##name)
+
+#define __X32_COMPAT_SYS_STUBx(x, name, ...) \
+ __SYS_STUBx(x64, compat_sys##name, \
+ SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __X32_COMPAT_COND_SYSCALL(name) \
+ __COND_SYSCALL(x64, compat_sys_##name)
+
+#define __X32_COMPAT_SYS_NI(name) \
+ __SYS_NI(x64, compat_sys_##name)
+#else /* CONFIG_X86_X32_ABI */
+#define __X32_COMPAT_SYS_STUB0(name)
+#define __X32_COMPAT_SYS_STUBx(x, name, ...)
+#define __X32_COMPAT_COND_SYSCALL(name)
+#define __X32_COMPAT_SYS_NI(name)
+#endif /* CONFIG_X86_X32_ABI */
+
+
+#ifdef CONFIG_COMPAT
+/*
+ * Compat means IA32_EMULATION and/or X86_X32. As they use a different
+ * mapping of registers to parameters, we need to generate stubs for each
+ * of them.
+ */
+#define COMPAT_SYSCALL_DEFINE0(name) \
+ static long \
+ __do_compat_sys_##name(const struct pt_regs *__unused); \
+ __IA32_COMPAT_SYS_STUB0(name) \
+ __X32_COMPAT_SYS_STUB0(name) \
+ static long \
+ __do_compat_sys_##name(const struct pt_regs *__unused)
+
+#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
+ static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
+ __IA32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \
+ __X32_COMPAT_SYS_STUBx(x, name, __VA_ARGS__) \
+ static long __se_compat_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__));\
+ } \
+ static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+/*
+ * As some compat syscalls may not be implemented, we need to expand
+ * COND_SYSCALL_COMPAT in kernel/sys_ni.c and COMPAT_SYS_NI in
+ * kernel/time/posix-stubs.c to cover this case as well.
+ */
+#define COND_SYSCALL_COMPAT(name) \
+ __IA32_COMPAT_COND_SYSCALL(name) \
+ __X32_COMPAT_COND_SYSCALL(name)
+
+#define COMPAT_SYS_NI(name) \
+ __IA32_COMPAT_SYS_NI(name) \
+ __X32_COMPAT_SYS_NI(name)
+
+#endif /* CONFIG_COMPAT */
+
+#define __SYSCALL_DEFINEx(x, name, ...) \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
+ __X64_SYS_STUBx(x, name, __VA_ARGS__) \
+ __IA32_SYS_STUBx(x, name, __VA_ARGS__) \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\
+ __MAP(x,__SC_TEST,__VA_ARGS__); \
+ __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
+ return ret; \
+ } \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+/*
+ * As the generic SYSCALL_DEFINE0() macro does not decode any parameters for
+ * obvious reasons, and passing struct pt_regs *regs to it in %rdi does not
+ * hurt, we only need to re-define it here to keep the naming congruent to
+ * SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI()
+ * macros to work correctly.
+ */
+#define SYSCALL_DEFINE0(sname) \
+ SYSCALL_METADATA(_##sname, 0); \
+ static long __do_sys_##sname(const struct pt_regs *__unused); \
+ __X64_SYS_STUB0(sname) \
+ __IA32_SYS_STUB0(sname) \
+ static long __do_sys_##sname(const struct pt_regs *__unused)
+
+#define COND_SYSCALL(name) \
+ __X64_COND_SYSCALL(name) \
+ __IA32_COND_SYSCALL(name)
+
+#define SYS_NI(name) \
+ __X64_SYS_NI(name) \
+ __IA32_SYS_NI(name)
+
+
+/*
+ * For VSYSCALLS, we need to declare these three syscalls with the new
+ * pt_regs-based calling convention for in-kernel use.
+ */
+long __x64_sys_getcpu(const struct pt_regs *regs);
+long __x64_sys_gettimeofday(const struct pt_regs *regs);
+long __x64_sys_time(const struct pt_regs *regs);
+
+#endif /* _ASM_X86_SYSCALL_WRAPPER_H */