diff options
Diffstat (limited to 'sysdeps/mach/hurd/i386/tls.h')
| -rw-r--r-- | sysdeps/mach/hurd/i386/tls.h | 50 |
1 files changed, 38 insertions, 12 deletions
diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h index 9108346..a7c291c 100644 --- a/sysdeps/mach/hurd/i386/tls.h +++ b/sysdeps/mach/hurd/i386/tls.h @@ -45,21 +45,24 @@ # include <errno.h> # include <assert.h> +#define HURD_TLS_DESC_DECL(desc, tcb) \ + struct descriptor desc = \ + { /* low word: */ \ + 0xffff /* limit 0..15 */ \ + | (((unsigned int) (tcb)) << 16) /* base 0..15 */ \ + , /* high word: */ \ + ((((unsigned int) (tcb)) >> 16) & 0xff) /* base 16..23 */ \ + | ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */ \ + | (0xf << 16) /* limit 16..19 */ \ + | ((4 | 8) << 20) /* granularity = SZ_32|SZ_G */ \ + | (((unsigned int) (tcb)) & 0xff000000) /* base 24..31 */ \ + } + + static inline const char * __attribute__ ((unused)) _hurd_tls_init (tcbhead_t *tcb, int secondcall) { - const unsigned int base = (unsigned int) tcb; - struct descriptor desc = - { /* low word: */ - 0xffff /* limit 0..15 */ - | (base << 16) /* base 0..15 */ - , /* high word: */ - ((base >> 16) & 0xff) /* base 16..23 */ - | ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */ - | (0xf << 16) /* limit 16..19 */ - | ((4 | 8) << 20) /* granularity = SZ_32|SZ_G */ - | (base & 0xff000000) /* base 24..31 */ - }; + HURD_TLS_DESC_DECL (desc, tcb); if (!secondcall) { @@ -140,6 +143,29 @@ _hurd_tls_init (tcbhead_t *tcb, int secondcall) asm ("movl %%gs:%P1,%0" : "=q" (_dtv) : "i" (offsetof (tcbhead_t, dtv)));\ _dtv; }) +/* Set up TLS in the new thread of a fork child, copying from our own. */ +static inline error_t __attribute__ ((unused)) +_hurd_tls_fork (thread_t child, struct machine_thread_state *state) +{ + /* Fetch the selector set by _hurd_tls_init. */ + int sel; + asm ("mov %%gs, %w0" : "=q" (sel)); + if (sel == state->ds) /* _hurd_tls_init was never called. */ + return 0; + + tcbhead_t *const tcb = THREAD_SELF; + HURD_TLS_DESC_DECL (desc, tcb); + error_t err; + + if (__builtin_expect (sel, 0x50) & 4) /* LDT selector */ + err = __i386_set_ldt (child, sel, &desc, 1); + else + err = __i386_set_gdt (child, &sel, desc); + + state->gs = sel; + return err; +} + # endif /* !ASSEMBLER */ #endif /* HAVE_TLS_SUPPORT */ |