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Improve support for XSAVE with debuggers.

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- Dump an NT_X86_XSTATE note if XSAVE is in use. This note is designed
  to match what Linux does in that 1) it dumps the entire XSAVE area
  including the fxsave state, and 2) it stashes a copy of the current
  xsave mask in the unused padding between the fxsave state and the
  xstate header at the same location used by Linux.
- Teach readelf() to recognize NT_X86_XSTATE notes.
- Change PT_GET/SETXSTATE to take the entire XSAVE state instead of
  only the extra portion. This avoids having to always make two
  ptrace() calls to get or set the full XSAVE state.
- Add a PT_GET_XSTATE_INFO which returns the length of the current
  XSTATE save area (so the size of the buffer needed for PT_GETXSTATE)
  and the current XSAVE mask (%xcr0).

Differential Revision:	https://reviews.freebsd.org/D1193
Reviewed by:	kib
MFC after:	2 weeks
This commit is contained in:
John Baldwin 2014-11-21 20:53:17 +00:00
parent 1e7bf26b33
commit 180e57e5c7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=274817
15 changed files with 259 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
contrib/binutils/binutils/readelf.c
View File

@ -9159,6 +9159,8 @@ get_freebsd_note_type (unsigned e_type)
return _("NT_PROCSTAT_PSSTRINGS (ps_strings data)");
case NT_PROCSTAT_AUXV:
return _("NT_PROCSTAT_AUXV (auxv data)");
case NT_X86_XSTATE:
return _("NT_X86_XSTATE (x86 XSAVE extended state)");
default:
return get_note_type(e_type);
}

1
contrib/binutils/include/elf/common.h
View File

@ -414,6 +414,7 @@
#define NT_PROCSTAT_OSREL 14
#define NT_PROCSTAT_PSSTRINGS 15
#define NT_PROCSTAT_AUXV 16
#define NT_X86_XSTATE 0x202
/* Note segments for core files on NetBSD systems. Note name

22
sys/amd64/amd64/elf_machdep.c
View File

@ -44,6 +44,7 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_param.h>
#include <machine/elf.h>
#include <machine/fpu.h>
#include <machine/md_var.h>
struct sysentvec elf64_freebsd_sysvec = {
@ -133,11 +134,26 @@ SYSINIT(kelf64, SI_SUB_EXEC, SI_ORDER_ANY,
&kfreebsd_brand_info);
void
elf64_dump_thread(struct thread *td __unused, void *dst __unused,
size_t *off __unused)
elf64_dump_thread(struct thread *td, void *dst, size_t *off)
{
}
void *buf;
size_t len;
len = 0;
if (use_xsave) {
if (dst != NULL) {
fpugetregs(td);
len += elf64_populate_note(NT_X86_XSTATE,
get_pcb_user_save_td(td), dst,
cpu_max_ext_state_size, &buf);
*(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
xsave_mask;
} else
len += elf64_populate_note(NT_X86_XSTATE, NULL, NULL,
cpu_max_ext_state_size, NULL);
}
*off = len;
}
/* Process one elf relocation with addend. */
static int

7
sys/amd64/amd64/fpu.c
View File

@ -127,6 +127,13 @@ CTASSERT(sizeof(struct savefpu_ymm) == 832);
*/
CTASSERT(sizeof(struct pcb) % XSAVE_AREA_ALIGN == 0);
/*
* Ensure the copy of XCR0 saved in a core is contained in the padding
* area.
*/
CTASSERT(X86_XSTATE_XCR0_OFFSET >= offsetof(struct savefpu, sv_pad) &&
X86_XSTATE_XCR0_OFFSET + sizeof(uint64_t) <= sizeof(struct savefpu));
static void fpu_clean_state(void);
SYSCTL_INT(_hw, HW_FLOATINGPT, floatingpoint, CTLFLAG_RD,

58
sys/amd64/amd64/ptrace_machdep.c
View File

@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
static int
cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
{
struct ptrace_xstate_info info;
char *savefpu;
int error;
@ -49,14 +50,14 @@ cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
return (EOPNOTSUPP);
switch (req) {
case PT_GETXSTATE:
case PT_GETXSTATE_OLD:
fpugetregs(td);
savefpu = (char *)(get_pcb_user_save_td(td) + 1);
error = copyout(savefpu, addr,
cpu_max_ext_state_size - sizeof(struct savefpu));
break;
case PT_SETXSTATE:
case PT_SETXSTATE_OLD:
if (data > cpu_max_ext_state_size - sizeof(struct savefpu)) {
error = EINVAL;
break;
@ -70,6 +71,36 @@ cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
free(savefpu, M_TEMP);
break;
case PT_GETXSTATE_INFO:
if (data != sizeof(info)) {
error = EINVAL;
break;
}
info.xsave_len = cpu_max_ext_state_size;
info.xsave_mask = xsave_mask;
error = copyout(&info, addr, data);
break;
case PT_GETXSTATE:
fpugetregs(td);
savefpu = (char *)(get_pcb_user_save_td(td));
error = copyout(savefpu, addr, cpu_max_ext_state_size);
break;
case PT_SETXSTATE:
if (data > cpu_max_ext_state_size) {
error = EINVAL;
break;
}
savefpu = malloc(data, M_TEMP, M_WAITOK);
error = copyin(addr, savefpu, data);
if (error == 0)
error = fpusetregs(td, (struct savefpu *)savefpu,
savefpu + sizeof(struct savefpu), data -
sizeof(struct savefpu));
free(savefpu, M_TEMP);
break;
default:
error = EINVAL;
break;
@ -81,8 +112,6 @@ cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
#ifdef COMPAT_FREEBSD32
#define PT_I386_GETXMMREGS (PT_FIRSTMACH + 0)
#define PT_I386_SETXMMREGS (PT_FIRSTMACH + 1)
#define PT_I386_GETXSTATE (PT_FIRSTMACH + 2)
#define PT_I386_SETXSTATE (PT_FIRSTMACH + 3)
static int
cpu32_ptrace(struct thread *td, int req, void *addr, int data)
@ -104,12 +133,12 @@ cpu32_ptrace(struct thread *td, int req, void *addr, int data)
fpstate->sv_env.en_mxcsr &= cpu_mxcsr_mask;
break;
case PT_I386_GETXSTATE:
error = cpu_ptrace_xstate(td, PT_GETXSTATE, addr, data);
break;
case PT_I386_SETXSTATE:
error = cpu_ptrace_xstate(td, PT_SETXSTATE, addr, data);
case PT_GETXSTATE_OLD:
case PT_SETXSTATE_OLD:
case PT_GETXSTATE_INFO:
case PT_GETXSTATE:
case PT_SETXSTATE:
error = cpu_ptrace_xstate(td, req, addr, data);
break;
default:
@ -131,13 +160,16 @@ cpu_ptrace(struct thread *td, int req, void *addr, int data)
return (cpu32_ptrace(td, req, addr, data));
#endif
/* Support old values of PT_GETXSTATE and PT_SETXSTATE. */
/* Support old values of PT_GETXSTATE_OLD and PT_SETXSTATE_OLD. */
if (req == PT_FIRSTMACH + 0)
req = PT_GETXSTATE;
req = PT_GETXSTATE_OLD;
if (req == PT_FIRSTMACH + 1)
req = PT_SETXSTATE;
req = PT_SETXSTATE_OLD;
switch (req) {
case PT_GETXSTATE_OLD:
case PT_SETXSTATE_OLD:
case PT_GETXSTATE_INFO:
case PT_GETXSTATE:
case PT_SETXSTATE:
error = cpu_ptrace_xstate(td, req, addr, data);

20
sys/compat/ia32/ia32_sysvec.c
View File

@ -187,9 +187,25 @@ SYSINIT(kia32, SI_SUB_EXEC, SI_ORDER_ANY,
&kia32_brand_info);
void
elf32_dump_thread(struct thread *td __unused, void *dst __unused,
size_t *off __unused)
elf32_dump_thread(struct thread *td, void *dst, size_t *off)
{
void *buf;
size_t len;
len = 0;
if (use_xsave) {
if (dst != NULL) {
fpugetregs(td);
len += elf32_populate_note(NT_X86_XSTATE,
get_pcb_user_save_td(td), dst,
cpu_max_ext_state_size, &buf);
*(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
xsave_mask;
} else
len += elf32_populate_note(NT_X86_XSTATE, NULL, NULL,
cpu_max_ext_state_size, NULL);
}
*off = len;
}
void

22
sys/i386/i386/elf_machdep.c
View File

@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
#include <machine/elf.h>
#include <machine/md_var.h>
#include <machine/npx.h>
struct sysentvec elf32_freebsd_sysvec = {
.sv_size = SYS_MAXSYSCALL,
@ -134,11 +135,26 @@ SYSINIT(kelf32, SI_SUB_EXEC, SI_ORDER_ANY,
void
elf32_dump_thread(struct thread *td __unused, void *dst __unused,
size_t *off __unused)
elf32_dump_thread(struct thread *td, void *dst, size_t *off)
{
}
void *buf;
size_t len;
len = 0;
if (use_xsave) {
if (dst != NULL) {
npxgetregs(td);
len += elf32_populate_note(NT_X86_XSTATE,
get_pcb_user_save_td(td), dst,
cpu_max_ext_state_size, &buf);
*(uint64_t *)((char *)buf + X86_XSTATE_XCR0_OFFSET) =
xsave_mask;
} else
len += elf32_populate_note(NT_X86_XSTATE, NULL, NULL,
cpu_max_ext_state_size, NULL);
}
*off = len;
}
/* Process one elf relocation with addend. */
static int

38
sys/i386/i386/ptrace_machdep.c
View File

@ -46,6 +46,7 @@ __FBSDID("$FreeBSD$");
static int
cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
{
struct ptrace_xstate_info info;
char *savefpu;
int error;
@ -53,14 +54,14 @@ cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
return (EOPNOTSUPP);
switch (req) {
case PT_GETXSTATE:
case PT_GETXSTATE_OLD:
npxgetregs(td);
savefpu = (char *)(get_pcb_user_save_td(td) + 1);
error = copyout(savefpu, addr,
cpu_max_ext_state_size - sizeof(union savefpu));
break;
case PT_SETXSTATE:
case PT_SETXSTATE_OLD:
if (data > cpu_max_ext_state_size - sizeof(union savefpu)) {
error = EINVAL;
break;
@ -74,6 +75,36 @@ cpu_ptrace_xstate(struct thread *td, int req, void *addr, int data)
free(savefpu, M_TEMP);
break;
case PT_GETXSTATE_INFO:
if (data != sizeof(info)) {
error = EINVAL;
break;
}
info.xsave_len = cpu_max_ext_state_size;
info.xsave_mask = xsave_mask;
error = copyout(&info, addr, data);
break;
case PT_GETXSTATE:
npxgetregs(td);
savefpu = (char *)(get_pcb_user_save_td(td));
error = copyout(savefpu, addr, cpu_max_ext_state_size);
break;
case PT_SETXSTATE:
if (data > cpu_max_ext_state_size) {
error = EINVAL;
break;
}
savefpu = malloc(data, M_TEMP, M_WAITOK);
error = copyin(addr, savefpu, data);
if (error == 0)
error = npxsetregs(td, (union savefpu *)savefpu,
savefpu + sizeof(union savefpu), data -
sizeof(union savefpu));
free(savefpu, M_TEMP);
break;
default:
error = EINVAL;
break;
@ -106,6 +137,9 @@ cpu_ptrace(struct thread *td, int req, void *addr, int data)
fpstate->sv_env.en_mxcsr &= cpu_mxcsr_mask;
break;
case PT_GETXSTATE_OLD:
case PT_SETXSTATE_OLD:
case PT_GETXSTATE_INFO:
case PT_GETXSTATE:
case PT_SETXSTATE:
error = cpu_ptrace_xstate(td, req, addr, data);

7
sys/i386/isa/npx.c
View File

@ -201,6 +201,13 @@ CTASSERT(sizeof(struct savefpu_ymm) == 832);
*/
CTASSERT(sizeof(struct pcb) % XSAVE_AREA_ALIGN == 0);
/*
* Ensure the copy of XCR0 saved in a core is contained in the padding
* area.
*/
CTASSERT(X86_XSTATE_XCR0_OFFSET >= offsetof(struct savexmm, sv_pad) &&
X86_XSTATE_XCR0_OFFSET + sizeof(uint64_t) <= sizeof(struct savexmm));
static void fpu_clean_state(void);
#endif

49
sys/kern/imgact_elf.c
View File

@ -1587,7 +1587,50 @@ register_note(struct note_info_list *list, int type, outfunc_t out, void *arg)
return (size);
notesize = sizeof(Elf_Note) + /* note header */
roundup2(8, ELF_NOTE_ROUNDSIZE) + /* note name ("FreeBSD") */
roundup2(sizeof(FREEBSD_ABI_VENDOR), ELF_NOTE_ROUNDSIZE) +
/* note name */
roundup2(size, ELF_NOTE_ROUNDSIZE); /* note description */
return (notesize);
}
static size_t
append_note_data(const void *src, void *dst, size_t len)
{
size_t padded_len;
padded_len = roundup2(len, ELF_NOTE_ROUNDSIZE);
if (dst != NULL) {
bcopy(src, dst, len);
bzero((char *)dst + len, padded_len - len);
}
return (padded_len);
}
size_t
__elfN(populate_note)(int type, void *src, void *dst, size_t size, void **descp)
{
Elf_Note *note;
char *buf;
size_t notesize;
buf = dst;
if (buf != NULL) {
note = (Elf_Note *)buf;
note->n_namesz = sizeof(FREEBSD_ABI_VENDOR);
note->n_descsz = size;
note->n_type = type;
buf += sizeof(*note);
buf += append_note_data(FREEBSD_ABI_VENDOR, buf,
sizeof(FREEBSD_ABI_VENDOR));
append_note_data(src, buf, size);
if (descp != NULL)
*descp = buf;
}
notesize = sizeof(Elf_Note) + /* note header */
roundup2(sizeof(FREEBSD_ABI_VENDOR), ELF_NOTE_ROUNDSIZE) +
/* note name */
roundup2(size, ELF_NOTE_ROUNDSIZE); /* note description */
return (notesize);
@ -1604,13 +1647,13 @@ __elfN(putnote)(struct note_info *ninfo, struct sbuf *sb)
return;
}
note.n_namesz = 8; /* strlen("FreeBSD") + 1 */
note.n_namesz = sizeof(FREEBSD_ABI_VENDOR);
note.n_descsz = ninfo->outsize;
note.n_type = ninfo->type;
sbuf_bcat(sb, &note, sizeof(note));
sbuf_start_section(sb, &old_len);
sbuf_bcat(sb, "FreeBSD", note.n_namesz);
sbuf_bcat(sb, FREEBSD_ABI_VENDOR, sizeof(FREEBSD_ABI_VENDOR));
sbuf_end_section(sb, old_len, ELF_NOTE_ROUNDSIZE, 0);
if (note.n_descsz == 0)
return;

1
sys/sys/elf_common.h
View File

@ -508,6 +508,7 @@ typedef struct {
#define NT_PROCSTAT_OSREL 14 /* Procstat osreldate data. */
#define NT_PROCSTAT_PSSTRINGS 15 /* Procstat ps_strings data. */
#define NT_PROCSTAT_AUXV 16 /* Procstat auxv data. */
#define NT_X86_XSTATE 0x202 /* x86 XSAVE extended state. */
/* Symbol Binding - ELFNN_ST_BIND - st_info */
#define STB_LOCAL 0 /* Local symbol */

1
sys/sys/imgact_elf.h
View File

@ -90,6 +90,7 @@ int __elfN(insert_brand_entry)(Elf_Brandinfo *entry);
int __elfN(remove_brand_entry)(Elf_Brandinfo *entry);
int __elfN(freebsd_fixup)(register_t **, struct image_params *);
int __elfN(coredump)(struct thread *, struct vnode *, off_t, int);
size_t __elfN(populate_note)(int, void *, void *, size_t, void **);
/* Machine specific function to dump per-thread information. */
void __elfN(dump_thread)(struct thread *, void *, size_t *);

17
sys/x86/include/fpu.h
View File

@ -63,15 +63,7 @@ struct save87 {
struct env87 sv_env; /* floating point control/status */
struct fpacc87 sv_ac[8]; /* accumulator contents, 0-7 */
uint8_t sv_pad0[4]; /* saved status word (now unused) */
/*
* Bogus padding for emulators. Emulators should use their own
* struct and arrange to store into this struct (ending here)
* before it is inspected for ptracing or for core dumps. Some
* emulators overwrite the whole struct. We have no good way of
* knowing how much padding to leave. Leave just enough for the
* GPL emulator's i387_union (176 bytes total).
*/
uint8_t sv_pad[64]; /* padding; used by emulators */
uint8_t sv_pad[64];
};
/* Contents of each SSE extended accumulator. */
@ -215,4 +207,11 @@ struct savefpu_ymm {
#define __INITIAL_MXCSR__ 0x1F80
#define __INITIAL_MXCSR_MASK__ 0xFFBF
/*
* The current value of %xcr0 is saved in the sv_pad[] field of the FPU
* state in the NT_X86_XSTATE note in core dumps. This offset is chosen
* to match the offset used by NT_X86_XSTATE in other systems.
*/
#define X86_XSTATE_XCR0_OFFSET 464
#endif /* !_X86_FPU_H_ */

17
sys/x86/include/ptrace.h
View File

@ -37,14 +37,25 @@
/*
* On amd64 (PT_FIRSTMACH + 0) and (PT_FIRSTMACH + 1) are old values for
* PT_GETXSTATE and PT_SETXSTATE. They should not be (re)used.
* PT_GETXSTATE_OLD and PT_SETXSTATE_OLD. They should not be (re)used.
*/
#ifdef __i386__
#define PT_GETXMMREGS (PT_FIRSTMACH + 0)
#define PT_SETXMMREGS (PT_FIRSTMACH + 1)
#endif
#define PT_GETXSTATE (PT_FIRSTMACH + 2)
#define PT_SETXSTATE (PT_FIRSTMACH + 3)
#ifdef _KERNEL
#define PT_GETXSTATE_OLD (PT_FIRSTMACH + 2)
#define PT_SETXSTATE_OLD (PT_FIRSTMACH + 3)
#endif
#define PT_GETXSTATE_INFO (PT_FIRSTMACH + 4)
#define PT_GETXSTATE (PT_FIRSTMACH + 5)
#define PT_SETXSTATE (PT_FIRSTMACH + 6)
/* Argument structure for PT_GETXSTATE_INFO. */
struct ptrace_xstate_info {
uint64_t xsave_mask;
uint32_t xsave_len;
};
#endif

35
usr.bin/gcore/elfcore.c
View File

@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
@ -101,6 +102,9 @@ static void *elf_note_fpregset(void *, size_t *);
static void *elf_note_prpsinfo(void *, size_t *);
static void *elf_note_prstatus(void *, size_t *);
static void *elf_note_thrmisc(void *, size_t *);
#if defined(__i386__) || defined(__amd64__)
static void *elf_note_x86_xstate(void *, size_t *);
#endif
static void *elf_note_procstat_auxv(void *, size_t *);
static void *elf_note_procstat_files(void *, size_t *);
static void *elf_note_procstat_groups(void *, size_t *);
@ -341,6 +345,9 @@ elf_putnotes(pid_t pid, struct sbuf *sb, size_t *sizep)
elf_putnote(NT_PRSTATUS, elf_note_prstatus, tids + i, sb);
elf_putnote(NT_FPREGSET, elf_note_fpregset, tids + i, sb);
elf_putnote(NT_THRMISC, elf_note_thrmisc, tids + i, sb);
#if defined(__i386__) || defined(__amd64__)
elf_putnote(NT_X86_XSTATE, elf_note_x86_xstate, tids + i, sb);
#endif
}
#ifndef ELFCORE_COMPAT_32
@ -615,6 +622,34 @@ elf_note_thrmisc(void *arg, size_t *sizep)
return (thrmisc);
}
#if defined(__i386__) || defined(__amd64__)
static void *
elf_note_x86_xstate(void *arg, size_t *sizep)
{
lwpid_t tid;
char *xstate;
static bool xsave_checked = false;
static struct ptrace_xstate_info info;
tid = *(lwpid_t *)arg;
if (!xsave_checked) {
if (ptrace(PT_GETXSTATE_INFO, tid, (void *)&info,
sizeof(info)) != 0)
info.xsave_len = 0;
xsave_checked = true;
}
if (info.xsave_len == 0) {
*sizep = 0;
return (NULL);
}
xstate = calloc(1, info.xsave_len);
ptrace(PT_GETXSTATE, tid, xstate, 0);
*(uint64_t *)(xstate + X86_XSTATE_XCR0_OFFSET) = info.xsave_mask;
*sizep = info.xsave_len;
return (xstate);
}
#endif
static void *
procstat_sysctl(void *arg, int what, size_t structsz, size_t *sizep)
{