diff options
Diffstat (limited to 'arch/x86/include/asm/ptrace.h')
| -rw-r--r-- | arch/x86/include/asm/ptrace.h | 377 |
1 files changed, 304 insertions, 73 deletions
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 942a08623a1a..35d062a2e304 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_X86_PTRACE_H #define _ASM_X86_PTRACE_H @@ -5,10 +6,24 @@ #include <asm/page_types.h> #include <uapi/asm/ptrace.h> -#ifndef __ASSEMBLY__ +#ifndef __ASSEMBLER__ #ifdef __i386__ struct pt_regs { + /* + * NB: 32-bit x86 CPUs are inconsistent as what happens in the + * following cases (where %seg represents a segment register): + * + * - pushl %seg: some do a 16-bit write and leave the high + * bits alone + * - movl %seg, [mem]: some do a 16-bit write despite the movl + * - IDT entry: some (e.g. 486) will leave the high bits of CS + * and (if applicable) SS undefined. + * + * Fortunately, x86-32 doesn't read the high bits on POP or IRET, + * so we can just treat all of the segment registers as 16-bit + * values. + */ unsigned long bx; unsigned long cx; unsigned long dx; @@ -16,28 +31,89 @@ struct pt_regs { unsigned long di; unsigned long bp; unsigned long ax; - unsigned long ds; - unsigned long es; - unsigned long fs; - unsigned long gs; + unsigned short ds; + unsigned short __dsh; + unsigned short es; + unsigned short __esh; + unsigned short fs; + unsigned short __fsh; + /* + * On interrupt, gs and __gsh store the vector number. They never + * store gs any more. + */ + unsigned short gs; + unsigned short __gsh; + /* On interrupt, this is the error code. */ unsigned long orig_ax; unsigned long ip; - unsigned long cs; + unsigned short cs; + unsigned short __csh; unsigned long flags; unsigned long sp; - unsigned long ss; + unsigned short ss; + unsigned short __ssh; }; #else /* __i386__ */ +struct fred_cs { + /* CS selector */ + u64 cs : 16, + /* Stack level at event time */ + sl : 2, + /* IBT in WAIT_FOR_ENDBRANCH state */ + wfe : 1, + : 45; +}; + +struct fred_ss { + /* SS selector */ + u64 ss : 16, + /* STI state */ + sti : 1, + /* Set if syscall, sysenter or INT n */ + swevent : 1, + /* Event is NMI type */ + nmi : 1, + : 13, + /* Event vector */ + vector : 8, + : 8, + /* Event type */ + type : 4, + : 4, + /* Event was incident to enclave execution */ + enclave : 1, + /* CPU was in 64-bit mode */ + l : 1, + /* + * Nested exception during FRED delivery, not set + * for #DF. + */ + nested : 1, + : 1, + /* + * The length of the instruction causing the event. + * Only set for INTO, INT1, INT3, INT n, SYSCALL + * and SYSENTER. 0 otherwise. + */ + insnlen : 4; +}; + struct pt_regs { + /* + * C ABI says these regs are callee-preserved. They aren't saved on + * kernel entry unless syscall needs a complete, fully filled + * "struct pt_regs". + */ unsigned long r15; unsigned long r14; unsigned long r13; unsigned long r12; unsigned long bp; unsigned long bx; -/* arguments: non interrupts/non tracing syscalls only save up to here*/ + + /* These regs are callee-clobbered. Always saved on kernel entry. */ unsigned long r11; unsigned long r10; unsigned long r9; @@ -47,70 +123,99 @@ struct pt_regs { unsigned long dx; unsigned long si; unsigned long di; + + /* + * orig_ax is used on entry for: + * - the syscall number (syscall, sysenter, int80) + * - error_code stored by the CPU on traps and exceptions + * - the interrupt number for device interrupts + * + * A FRED stack frame starts here: + * 1) It _always_ includes an error code; + * + * 2) The return frame for ERET[US] starts here, but + * the content of orig_ax is ignored. + */ unsigned long orig_ax; -/* end of arguments */ -/* cpu exception frame or undefined */ + + /* The IRETQ return frame starts here */ unsigned long ip; - unsigned long cs; + + union { + /* CS selector */ + u16 cs; + /* The extended 64-bit data slot containing CS */ + u64 csx; + /* The FRED CS extension */ + struct fred_cs fred_cs; + }; + unsigned long flags; unsigned long sp; - unsigned long ss; -/* top of stack page */ + + union { + /* SS selector */ + u16 ss; + /* The extended 64-bit data slot containing SS */ + u64 ssx; + /* The FRED SS extension */ + struct fred_ss fred_ss; + }; + + /* + * Top of stack on IDT systems, while FRED systems have extra fields + * defined above for storing exception related information, e.g. CR2 or + * DR6. + */ }; #endif /* !__i386__ */ -#include <linux/init.h> #ifdef CONFIG_PARAVIRT #include <asm/paravirt_types.h> #endif +#include <asm/proto.h> + struct cpuinfo_x86; struct task_struct; extern unsigned long profile_pc(struct pt_regs *regs); -#define profile_pc profile_pc extern unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs); -extern void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, - int error_code, int si_code); +extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code); -extern long syscall_trace_enter(struct pt_regs *); -extern void syscall_trace_leave(struct pt_regs *); -static inline unsigned long regs_return_value(struct pt_regs *regs) +static __always_inline unsigned long regs_return_value(struct pt_regs *regs) { return regs->ax; } -/* - * user_mode_vm(regs) determines whether a register set came from user mode. - * This is true if V8086 mode was enabled OR if the register set was from - * protected mode with RPL-3 CS value. This tricky test checks that with - * one comparison. Many places in the kernel can bypass this full check - * if they have already ruled out V8086 mode, so user_mode(regs) can be used. - */ -static inline int user_mode(struct pt_regs *regs) +static __always_inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) { -#ifdef CONFIG_X86_32 - return (regs->cs & SEGMENT_RPL_MASK) == USER_RPL; -#else - return !!(regs->cs & 3); -#endif + regs->ax = rc; } -static inline int user_mode_vm(struct pt_regs *regs) +/* + * user_mode(regs) determines whether a register set came from user + * mode. On x86_32, this is true if V8086 mode was enabled OR if the + * register set was from protected mode with RPL-3 CS value. This + * tricky test checks that with one comparison. + * + * On x86_64, vm86 mode is mercifully nonexistent, and we don't need + * the extra check. + */ +static __always_inline int user_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 - return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= - USER_RPL; + return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; #else - return user_mode(regs); + return !!(regs->cs & 3); #endif } -static inline int v8086_mode(struct pt_regs *regs) +static __always_inline int v8086_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 return (regs->flags & X86_VM_MASK); @@ -119,10 +224,10 @@ static inline int v8086_mode(struct pt_regs *regs) #endif } -#ifdef CONFIG_X86_64 static inline bool user_64bit_mode(struct pt_regs *regs) { -#ifndef CONFIG_PARAVIRT +#ifdef CONFIG_X86_64 +#ifndef CONFIG_PARAVIRT_XXL /* * On non-paravirt systems, this is the only long mode CPL 3 * selector. We do not allow long mode selectors in the LDT. @@ -132,30 +237,82 @@ static inline bool user_64bit_mode(struct pt_regs *regs) /* Headers are too twisted for this to go in paravirt.h. */ return regs->cs == __USER_CS || regs->cs == pv_info.extra_user_64bit_cs; #endif +#else /* !CONFIG_X86_64 */ + return false; +#endif } -#define current_user_stack_pointer() this_cpu_read(old_rsp) -/* ia32 vs. x32 difference */ -#define compat_user_stack_pointer() \ - (test_thread_flag(TIF_IA32) \ - ? current_pt_regs()->sp \ - : this_cpu_read(old_rsp)) +/* + * Determine whether the register set came from any context that is running in + * 64-bit mode. + */ +static inline bool any_64bit_mode(struct pt_regs *regs) +{ +#ifdef CONFIG_X86_64 + return !user_mode(regs) || user_64bit_mode(regs); +#else + return false; #endif +} -#ifdef CONFIG_X86_32 -extern unsigned long kernel_stack_pointer(struct pt_regs *regs); -#else -static inline unsigned long kernel_stack_pointer(struct pt_regs *regs) +#ifdef CONFIG_X86_64 +#define current_user_stack_pointer() current_pt_regs()->sp +#define compat_user_stack_pointer() current_pt_regs()->sp + +static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs) { - return regs->sp; + bool ret = (regs->ip >= (unsigned long)entry_SYSCALL_64 && + regs->ip < (unsigned long)entry_SYSCALL_64_safe_stack); + + ret = ret || (regs->ip >= (unsigned long)entry_SYSRETQ_unsafe_stack && + regs->ip < (unsigned long)entry_SYSRETQ_end); +#ifdef CONFIG_IA32_EMULATION + ret = ret || (regs->ip >= (unsigned long)entry_SYSCALL_compat && + regs->ip < (unsigned long)entry_SYSCALL_compat_safe_stack); + ret = ret || (regs->ip >= (unsigned long)entry_SYSRETL_compat_unsafe_stack && + regs->ip < (unsigned long)entry_SYSRETL_compat_end); +#endif + + return ret; } #endif -#define GET_IP(regs) ((regs)->ip) -#define GET_FP(regs) ((regs)->bp) -#define GET_USP(regs) ((regs)->sp) +static __always_inline unsigned long kernel_stack_pointer(struct pt_regs *regs) +{ + return regs->sp; +} -#include <asm-generic/ptrace.h> +static __always_inline unsigned long instruction_pointer(struct pt_regs *regs) +{ + return regs->ip; +} + +static __always_inline +void instruction_pointer_set(struct pt_regs *regs, unsigned long val) +{ + regs->ip = val; +} + +static __always_inline unsigned long frame_pointer(struct pt_regs *regs) +{ + return regs->bp; +} + +static __always_inline unsigned long user_stack_pointer(struct pt_regs *regs) +{ + return regs->sp; +} + +static __always_inline +void user_stack_pointer_set(struct pt_regs *regs, unsigned long val) +{ + regs->sp = val; +} + +static __always_inline bool regs_irqs_disabled(struct pt_regs *regs) +{ + return !(regs->flags & X86_EFLAGS_IF); +} /* Query offset/name of register from its name/offset */ extern int regs_query_register_offset(const char *name); @@ -177,13 +334,16 @@ static inline unsigned long regs_get_register(struct pt_regs *regs, if (unlikely(offset > MAX_REG_OFFSET)) return 0; #ifdef CONFIG_X86_32 - /* - * Traps from the kernel do not save sp and ss. - * Use the helper function to retrieve sp. - */ - if (offset == offsetof(struct pt_regs, sp) && - regs->cs == __KERNEL_CS) - return kernel_stack_pointer(regs); + /* The selector fields are 16-bit. */ + if (offset == offsetof(struct pt_regs, cs) || + offset == offsetof(struct pt_regs, ss) || + offset == offsetof(struct pt_regs, ds) || + offset == offsetof(struct pt_regs, es) || + offset == offsetof(struct pt_regs, fs) || + offset == offsetof(struct pt_regs, gs)) { + return *(u16 *)((unsigned long)regs + offset); + + } #endif return *(unsigned long *)((unsigned long)regs + offset); } @@ -199,28 +359,93 @@ static inline unsigned long regs_get_register(struct pt_regs *regs, static inline int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr) { - return ((addr & ~(THREAD_SIZE - 1)) == - (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))); + return ((addr & ~(THREAD_SIZE - 1)) == (regs->sp & ~(THREAD_SIZE - 1))); +} + +/** + * regs_get_kernel_stack_nth_addr() - get the address of the Nth entry on stack + * @regs: pt_regs which contains kernel stack pointer. + * @n: stack entry number. + * + * regs_get_kernel_stack_nth() returns the address of the @n th entry of the + * kernel stack which is specified by @regs. If the @n th entry is NOT in + * the kernel stack, this returns NULL. + */ +static inline unsigned long *regs_get_kernel_stack_nth_addr(struct pt_regs *regs, unsigned int n) +{ + unsigned long *addr = (unsigned long *)regs->sp; + + addr += n; + if (regs_within_kernel_stack(regs, (unsigned long)addr)) + return addr; + else + return NULL; } +/* To avoid include hell, we can't include uaccess.h */ +extern long copy_from_kernel_nofault(void *dst, const void *src, size_t size); + /** * regs_get_kernel_stack_nth() - get Nth entry of the stack * @regs: pt_regs which contains kernel stack pointer. * @n: stack entry number. * * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which - * is specified by @regs. If the @n th entry is NOT in the kernel stack, + * is specified by @regs. If the @n th entry is NOT in the kernel stack * this returns 0. */ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n) { - unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs); - addr += n; - if (regs_within_kernel_stack(regs, (unsigned long)addr)) - return *addr; - else - return 0; + unsigned long *addr; + unsigned long val; + long ret; + + addr = regs_get_kernel_stack_nth_addr(regs, n); + if (addr) { + ret = copy_from_kernel_nofault(&val, addr, sizeof(val)); + if (!ret) + return val; + } + return 0; +} + +/** + * regs_get_kernel_argument() - get Nth function argument in kernel + * @regs: pt_regs of that context + * @n: function argument number (start from 0) + * + * regs_get_argument() returns @n th argument of the function call. + * Note that this chooses most probably assignment, in some case + * it can be incorrect. + * This is expected to be called from kprobes or ftrace with regs + * where the top of stack is the return address. + */ +static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, + unsigned int n) +{ + static const unsigned int argument_offs[] = { +#ifdef __i386__ + offsetof(struct pt_regs, ax), + offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, cx), +#define NR_REG_ARGUMENTS 3 +#else + offsetof(struct pt_regs, di), + offsetof(struct pt_regs, si), + offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, r8), + offsetof(struct pt_regs, r9), +#define NR_REG_ARGUMENTS 6 +#endif + }; + + if (n >= NR_REG_ARGUMENTS) { + n -= NR_REG_ARGUMENTS - 1; + return regs_get_kernel_stack_nth(regs, n); + } else + return regs_get_register(regs, argument_offs[n]); } #define arch_has_single_step() (1) @@ -230,7 +455,7 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, #define arch_has_block_step() (boot_cpu_data.x86 >= 6) #endif -#define ARCH_HAS_USER_SINGLE_STEP_INFO +#define ARCH_HAS_USER_SINGLE_STEP_REPORT struct user_desc; extern int do_get_thread_area(struct task_struct *p, int idx, @@ -238,5 +463,11 @@ extern int do_get_thread_area(struct task_struct *p, int idx, extern int do_set_thread_area(struct task_struct *p, int idx, struct user_desc __user *info, int can_allocate); -#endif /* !__ASSEMBLY__ */ +#ifdef CONFIG_X86_64 +# define do_set_thread_area_64(p, s, t) do_arch_prctl_64(p, s, t) +#else +# define do_set_thread_area_64(p, s, t) (0) +#endif + +#endif /* !__ASSEMBLER__ */ #endif /* _ASM_X86_PTRACE_H */ |