diff options
| -rw-r--r-- | arch/x86/um/os-Linux/mcontext.c | 218 | ||||
| -rw-r--r-- | arch/x86/um/ptrace.c | 76 | ||||
| -rw-r--r-- | arch/x86/um/shared/sysdep/mcontext.h | 9 |
3 files changed, 283 insertions, 20 deletions
diff --git a/arch/x86/um/os-Linux/mcontext.c b/arch/x86/um/os-Linux/mcontext.c index 37decaa74761..e661fdc44db9 100644 --- a/arch/x86/um/os-Linux/mcontext.c +++ b/arch/x86/um/os-Linux/mcontext.c @@ -1,7 +1,10 @@ // SPDX-License-Identifier: GPL-2.0 -#include <sys/ucontext.h> #define __FRAME_OFFSETS +#include <linux/errno.h> +#include <linux/string.h> +#include <sys/ucontext.h> #include <asm/ptrace.h> +#include <asm/sigcontext.h> #include <sysdep/ptrace.h> #include <sysdep/mcontext.h> #include <arch.h> @@ -18,6 +21,10 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc) COPY2(UESP, ESP); /* sic */ COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX); COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS); +#undef COPY2 +#undef COPY +#undef COPY_SEG +#undef COPY_SEG_CPL3 #else #define COPY2(X,Y) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##Y] #define COPY(X) regs->gp[X/sizeof(unsigned long)] = mc->gregs[REG_##X] @@ -29,6 +36,8 @@ void get_regs_from_mc(struct uml_pt_regs *regs, mcontext_t *mc) COPY2(EFLAGS, EFL); COPY2(CS, CSGSFS); regs->gp[SS / sizeof(unsigned long)] = mc->gregs[REG_CSGSFS] >> 48; +#undef COPY2 +#undef COPY #endif } @@ -42,3 +51,210 @@ void mc_set_rip(void *_mc, void *target) mc->gregs[REG_RIP] = (unsigned long)target; #endif } + +/* Same thing, but the copy macros are turned around. */ +void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, int single_stepping) +{ +#ifdef __i386__ +#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X] +#define COPY(X) mc->gregs[REG_##X] = regs->gp[X] +#define COPY_SEG(X) mc->gregs[REG_##X] = regs->gp[X] & 0xffff; +#define COPY_SEG_CPL3(X) mc->gregs[REG_##X] = (regs->gp[X] & 0xffff) | 3; + COPY_SEG(GS); COPY_SEG(FS); COPY_SEG(ES); COPY_SEG(DS); + COPY(EDI); COPY(ESI); COPY(EBP); + COPY2(UESP, ESP); /* sic */ + COPY(EBX); COPY(EDX); COPY(ECX); COPY(EAX); + COPY(EIP); COPY_SEG_CPL3(CS); COPY(EFL); COPY_SEG_CPL3(SS); +#else +#define COPY2(X,Y) mc->gregs[REG_##Y] = regs->gp[X/sizeof(unsigned long)] +#define COPY(X) mc->gregs[REG_##X] = regs->gp[X/sizeof(unsigned long)] + COPY(R8); COPY(R9); COPY(R10); COPY(R11); + COPY(R12); COPY(R13); COPY(R14); COPY(R15); + COPY(RDI); COPY(RSI); COPY(RBP); COPY(RBX); + COPY(RDX); COPY(RAX); COPY(RCX); COPY(RSP); + COPY(RIP); + COPY2(EFLAGS, EFL); + mc->gregs[REG_CSGSFS] = mc->gregs[REG_CSGSFS] & 0xffffffffffffl; + mc->gregs[REG_CSGSFS] |= (regs->gp[SS / sizeof(unsigned long)] & 0xffff) << 48; +#endif + + if (single_stepping) + mc->gregs[REG_EFL] |= X86_EFLAGS_TF; + else + mc->gregs[REG_EFL] &= ~X86_EFLAGS_TF; +} + +#ifdef CONFIG_X86_32 +struct _xstate_64 { + struct _fpstate_64 fpstate; + struct _header xstate_hdr; + struct _ymmh_state ymmh; + /* New processor state extensions go here: */ +}; + +/* Not quite the right structures as these contain more information */ +int um_i387_from_fxsr(struct _fpstate_32 *i387, + const struct _fpstate_64 *fxsave); +int um_fxsr_from_i387(struct _fpstate_64 *fxsave, + const struct _fpstate_32 *from); +#else +#define _xstate_64 _xstate +#endif + +static struct _fpstate *get_fpstate(struct stub_data *data, + mcontext_t *mcontext, + int *fp_size) +{ + struct _fpstate *res; + + /* Assume floating point registers are on the same page */ + res = (void *)(((unsigned long)mcontext->fpregs & + (UM_KERN_PAGE_SIZE - 1)) + + (unsigned long)&data->sigstack[0]); + + if ((void *)res + sizeof(struct _fpstate) > + (void *)data->sigstack + sizeof(data->sigstack)) + return NULL; + + if (res->sw_reserved.magic1 != FP_XSTATE_MAGIC1) { + *fp_size = sizeof(struct _fpstate); + } else { + char *magic2_addr; + + magic2_addr = (void *)res; + magic2_addr += res->sw_reserved.extended_size; + magic2_addr -= FP_XSTATE_MAGIC2_SIZE; + + /* We still need to be within our stack */ + if ((void *)magic2_addr > + (void *)data->sigstack + sizeof(data->sigstack)) + return NULL; + + /* If we do not read MAGIC2, then we did something wrong */ + if (*(__u32 *)magic2_addr != FP_XSTATE_MAGIC2) + return NULL; + + /* Remove MAGIC2 from the size, we do not save/restore it */ + *fp_size = res->sw_reserved.extended_size - + FP_XSTATE_MAGIC2_SIZE; + } + + return res; +} + +int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data, + unsigned long *fp_size_out) +{ + mcontext_t *mcontext; + struct _fpstate *fpstate_stub; + struct _xstate_64 *xstate_stub; + int fp_size, xstate_size; + + /* mctx_offset is verified by wait_stub_done_seccomp */ + mcontext = (void *)&data->sigstack[data->mctx_offset]; + + get_regs_from_mc(regs, mcontext); + + fpstate_stub = get_fpstate(data, mcontext, &fp_size); + if (!fpstate_stub) + return -EINVAL; + +#ifdef CONFIG_X86_32 + xstate_stub = (void *)&fpstate_stub->_fxsr_env; + xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env); +#else + xstate_stub = (void *)fpstate_stub; + xstate_size = fp_size; +#endif + + if (fp_size_out) + *fp_size_out = xstate_size; + + if (xstate_size > host_fp_size) + return -ENOSPC; + + memcpy(®s->fp, xstate_stub, xstate_size); + + /* We do not need to read the x86_64 FS_BASE/GS_BASE registers as + * we do not permit userspace to set them directly. + */ + +#ifdef CONFIG_X86_32 + /* Read the i387 legacy FP registers */ + if (um_fxsr_from_i387((void *)®s->fp, fpstate_stub)) + return -EINVAL; +#endif + + return 0; +} + +/* Copied because we cannot include regset.h here. */ +struct task_struct; +struct user_regset; +struct membuf { + void *p; + size_t left; +}; + +int fpregs_legacy_get(struct task_struct *target, + const struct user_regset *regset, + struct membuf to); + +int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data, + int single_stepping) +{ + mcontext_t *mcontext; + struct _fpstate *fpstate_stub; + struct _xstate_64 *xstate_stub; + int fp_size, xstate_size; + + /* mctx_offset is verified by wait_stub_done_seccomp */ + mcontext = (void *)&data->sigstack[data->mctx_offset]; + + if ((unsigned long)mcontext < (unsigned long)data->sigstack || + (unsigned long)mcontext > + (unsigned long) data->sigstack + + sizeof(data->sigstack) - sizeof(*mcontext)) + return -EINVAL; + + get_mc_from_regs(regs, mcontext, single_stepping); + + fpstate_stub = get_fpstate(data, mcontext, &fp_size); + if (!fpstate_stub) + return -EINVAL; + +#ifdef CONFIG_X86_32 + xstate_stub = (void *)&fpstate_stub->_fxsr_env; + xstate_size = fp_size - offsetof(struct _fpstate_32, _fxsr_env); +#else + xstate_stub = (void *)fpstate_stub; + xstate_size = fp_size; +#endif + + memcpy(fpstate_stub, ®s->fp, fp_size); + +#ifdef __i386__ + /* + * On x86, the GDT entries are updated by arch_set_tls. + */ + + /* Store the i387 legacy FP registers which the host will use */ + if (um_i387_from_fxsr(fpstate_stub, (void *)®s->fp)) + return -EINVAL; +#else + /* + * On x86_64, we need to sync the FS_BASE/GS_BASE registers using the + * arch specific data. + */ + if (data->arch_data.fs_base != regs->gp[FS_BASE / sizeof(unsigned long)]) { + data->arch_data.fs_base = regs->gp[FS_BASE / sizeof(unsigned long)]; + data->arch_data.sync |= STUB_SYNC_FS_BASE; + } + if (data->arch_data.gs_base != regs->gp[GS_BASE / sizeof(unsigned long)]) { + data->arch_data.gs_base = regs->gp[GS_BASE / sizeof(unsigned long)]; + data->arch_data.sync |= STUB_SYNC_GS_BASE; + } +#endif + + return 0; +} diff --git a/arch/x86/um/ptrace.c b/arch/x86/um/ptrace.c index 57c504fd5626..3275870330fe 100644 --- a/arch/x86/um/ptrace.c +++ b/arch/x86/um/ptrace.c @@ -25,7 +25,8 @@ static inline unsigned short twd_i387_to_fxsr(unsigned short twd) return tmp; } -static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) +static inline unsigned long +twd_fxsr_to_i387(const struct user_fxsr_struct *fxsave) { struct _fpxreg *st = NULL; unsigned long twd = (unsigned long) fxsave->twd; @@ -69,12 +70,16 @@ static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) return ret; } -/* Get/set the old 32bit i387 registers (pre-FPX) */ -static int fpregs_legacy_get(struct task_struct *target, - const struct user_regset *regset, - struct membuf to) +/* + * Get/set the old 32bit i387 registers (pre-FPX) + * + * We provide simple wrappers for mcontext.c, they are only defined locally + * because mcontext.c is userspace facing and needs to a different definition + * of the structures. + */ +static int _um_i387_from_fxsr(struct membuf to, + const struct user_fxsr_struct *fxsave) { - struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp; int i; membuf_store(&to, (unsigned long)fxsave->cwd | 0xffff0000ul); @@ -91,23 +96,36 @@ static int fpregs_legacy_get(struct task_struct *target, return 0; } -static int fpregs_legacy_set(struct task_struct *target, +int um_i387_from_fxsr(struct user_i387_struct *i387, + const struct user_fxsr_struct *fxsave); + +int um_i387_from_fxsr(struct user_i387_struct *i387, + const struct user_fxsr_struct *fxsave) +{ + struct membuf to = { + .p = i387, + .left = sizeof(*i387), + }; + + return _um_i387_from_fxsr(to, fxsave); +} + +static int fpregs_legacy_get(struct task_struct *target, const struct user_regset *regset, - unsigned int pos, unsigned int count, - const void *kbuf, const void __user *ubuf) + struct membuf to) { struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp; - const struct user_i387_struct *from; - struct user_i387_struct buf; - int i; - if (ubuf) { - if (copy_from_user(&buf, ubuf, sizeof(buf))) - return -EFAULT; - from = &buf; - } else { - from = kbuf; - } + return _um_i387_from_fxsr(to, fxsave); +} + +int um_fxsr_from_i387(struct user_fxsr_struct *fxsave, + const struct user_i387_struct *from); + +int um_fxsr_from_i387(struct user_fxsr_struct *fxsave, + const struct user_i387_struct *from) +{ + int i; fxsave->cwd = (unsigned short)(from->cwd & 0xffff); fxsave->swd = (unsigned short)(from->swd & 0xffff); @@ -125,6 +143,26 @@ static int fpregs_legacy_set(struct task_struct *target, return 0; } + +static int fpregs_legacy_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + struct user_fxsr_struct *fxsave = (void *)target->thread.regs.regs.fp; + const struct user_i387_struct *from; + struct user_i387_struct buf; + + if (ubuf) { + if (copy_from_user(&buf, ubuf, sizeof(buf))) + return -EFAULT; + from = &buf; + } else { + from = kbuf; + } + + return um_fxsr_from_i387(fxsave, &buf); +} #endif static int genregs_get(struct task_struct *target, diff --git a/arch/x86/um/shared/sysdep/mcontext.h b/arch/x86/um/shared/sysdep/mcontext.h index b724c54da316..6fe490cc5b98 100644 --- a/arch/x86/um/shared/sysdep/mcontext.h +++ b/arch/x86/um/shared/sysdep/mcontext.h @@ -6,7 +6,16 @@ #ifndef __SYS_SIGCONTEXT_X86_H #define __SYS_SIGCONTEXT_X86_H +#include <stub-data.h> + extern void get_regs_from_mc(struct uml_pt_regs *, mcontext_t *); +extern void get_mc_from_regs(struct uml_pt_regs *regs, mcontext_t *mc, + int single_stepping); + +extern int get_stub_state(struct uml_pt_regs *regs, struct stub_data *data, + unsigned long *fp_size_out); +extern int set_stub_state(struct uml_pt_regs *regs, struct stub_data *data, + int single_stepping); #ifdef __i386__ |