niansa-misc/glibc
1
0
Fork 0
mirror of git://sourceware.org/git/glibc.git synced 2025-03-06 20:58:33 +01:00
Code Issues Projects Releases Packages Wiki Activity

hurd: Fix intr-msg parameter/stack kludge

Browse source 
INTR_MSG_TRAP was tinkering with esp to make it point to
_hurd_intr_rpc_mach_msg's parameters, and notably use (&msg)[-1] which is
meaningless in C.

Instead, just push the parameters on the stack, which also avoids leaving
local variables of _hurd_intr_rpc_mach_msg below esp. We now also
properly express that OPTION and TIMEOUT may be updated during the trap
call.
This commit is contained in:
Samuel Thibault 2021-10-18 00:43:23 +02:00
parent 9d3c9a046a
commit 1d20f33ff4
1 changed files with 39 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

49
sysdeps/mach/hurd/i386/intr-msg.h
View file

@ -21,8 +21,6 @@
to indicate that the signal thread might mutate them as part
of sending us to a signal handler. */
/* After _hurd_intr_rpc_msg_about_to we need to make a last check of cancel, in
case we got interrupted right before _hurd_intr_rpc_msg_about_to. */
#define INTR_MSG_TRAP(msg, option, send_size, rcv_size, rcv_name, timeout, notify, cancel_p, intr_port_p) \
({ \
error_t err; \
@ -31,21 +29,52 @@
".globl _hurd_intr_rpc_msg_do_trap\n" \
".globl _hurd_intr_rpc_msg_in_trap\n" \
".globl _hurd_intr_rpc_msg_sp_restored\n" \
"_hurd_intr_rpc_msg_about_to: cmpl $0, %5\n" \
"_hurd_intr_rpc_msg_about_to:" \
/* We need to make a last check of cancel, in case we got interrupted
right before _hurd_intr_rpc_msg_about_to. */ \
" cmpl $0, %5\n" \
" jz _hurd_intr_rpc_msg_do\n" \
/* We got interrupted, note so and return EINTR. */ \
" movl $0, %3\n" \
" movl %6, %%eax\n" \
" jmp _hurd_intr_rpc_msg_sp_restored\n" \
"_hurd_intr_rpc_msg_do: movl %%esp, %%ecx\n" \
" .cfi_def_cfa_register %%ecx\n" \
" leal %4, %%esp\n" \
"_hurd_intr_rpc_msg_do:" \
/* Ok, push the mach_msg_trap arguments. */ \
" pushl 24(%4)\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl %2\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl 16(%4)\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl 12(%4)\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl 8(%4)\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl %1\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl (%4)\n" \
" .cfi_adjust_cfa_offset 4\n" \
" pushl $0\n" \
" .cfi_adjust_cfa_offset 4\n" \
/* TODO: remove this ecx kludge, we don't need it any more */ \
" movl %%esp, %%ecx\n" \
"_hurd_intr_rpc_msg_cx_sp: movl $-25, %%eax\n" \
"_hurd_intr_rpc_msg_do_trap: lcall $7, $0 # status in %0\n" \
"_hurd_intr_rpc_msg_in_trap: movl %%ecx, %%esp\n" \
" .cfi_def_cfa_register %%esp\n" \
"_hurd_intr_rpc_msg_in_trap:" \
/* Ok, clean the arguments and update OPTION and TIMEOUT. */ \
" addl $8, %%esp\n" \
" .cfi_adjust_cfa_offset -8\n" \
" popl %1\n" \
" .cfi_adjust_cfa_offset -4\n" \
" addl $12, %%esp\n" \
" .cfi_adjust_cfa_offset -12\n" \
" popl %2\n" \
" .cfi_adjust_cfa_offset -4\n" \
" addl $4, %%esp\n" \
" .cfi_adjust_cfa_offset -4\n" \
"_hurd_intr_rpc_msg_sp_restored:" \
: "=a" (err), "+m" (option), "+m" (timeout), "=m" (*intr_port_p) \
: "m" ((&msg)[-1]), "m" (*cancel_p), "i" (EINTR) \
: "=a" (err), "+r" (option), "+r" (timeout), "=m" (*intr_port_p) \
: "r" (&msg), "m" (*cancel_p), "i" (EINTR) \
: "ecx"); \
err; \
})