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Port recent changes to mipsel systems

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* exec/exec.c (exec_0): Don't disable AT_EXECFN substitution on
MIPS systems.

* exec/loader-aarch64.s (skip_environ): Correct typo in
commentary.

* exec/loader-mips64el.s: Add a disclaimer that this file is
currently inoperable.

* exec/loader-mipsel.s (__start): Move environment and argument
vectors and produce and replace AT_EXECFN.  Clear stack before
proceeding to circumvent an oversight in glibc.
This commit is contained in:
Po Lu
2025-04-14 21:28:15 +08:00
parent 4918de1699
commit 74df372398
5 changed files with 224 additions and 101 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
exec/config-mips.m4.in
View File

@@ -18,6 +18,7 @@ dnl You should have received a copy of the GNU General Public License
dnl along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
define(`SYSCALL_open', `ifelse(`@MIPS_N32@',`yes',`6002',`4005')')
dnl define(`SYSCALL_openat', `ifelse(`@MIPS_N32@',`yes',`6251',`4288')')
define(`SYSCALL_close', `ifelse(`@MIPS_N32@',`yes',`6003',`4006')')
define(`SYSCALL_mmap', `ifelse(`@MIPS_N32@',`yes',`6009',`4090')')
define(`SYSCALL_nanosleep', `ifelse(`@MIPS_N32@',`yes',`6034',`4166')')
@@ -34,6 +35,7 @@ define(`SYSCALL', `ifelse(`@MIPS_N32@',`yes',` move $a4, $1
sw $4, 28($sp)')')
define(`RESTORE', `ifelse(`@MIPS_N32@',`yes',` nop',` addi $sp, 32')')
define(`FP', `ifelse(`@MIPS_N32@',`yes',`$s8',`$fp')')
dnl For mips64. Some assemblers don't want to assemble `daddi'.
define(`DADDI2', `ifelse(`@DADDI_BROKEN@',`yes',` li $at, $2

13
exec/exec.c
View File

@@ -231,10 +231,10 @@ struct exec_jump_command
/* The value of AT_BASE inside the aux vector. */
USER_WORD at_base;
#if defined __mips__ && !defined MIPS_NABI
/* The FPU mode to apply. */
#if defined __mips__
/* The FPU mode to apply. Not used when !MIPS_NABI. */
USER_WORD fpu_mode;
#endif /* defined __mips__ && !defined MIPS_NABI */
#endif /* defined __mips__ */
};
@@ -916,9 +916,7 @@ exec_0 (char *name, struct exec_tracee *tracee,
program_header program;
USER_WORD entry, program_entry, offset;
USER_WORD header_offset;
#ifndef __mips__
USER_WORD name_len, aligned_len;
#endif /* !__mips__ */
struct exec_jump_command jump;
#if defined __mips__ && !defined MIPS_NABI
int fpu_mode;
@@ -1132,6 +1130,8 @@ exec_0 (char *name, struct exec_tracee *tracee,
fpu_mode = FP_FRE;
jump.fpu_mode = fpu_mode;
#elif defined __mips__
jump.fpu_mode = 0;
#endif /* defined __mips__ && !defined MIPS_NABI */
/* The offset used for at_phdr should be that of the first
@@ -1149,8 +1149,6 @@ exec_0 (char *name, struct exec_tracee *tracee,
sizeof jump);
loader_area_used += sizeof jump;
/* TODO: MIPS support. */
#ifndef __mips__
/* Copy the length of NAME and NAME itself to the loader area. */
name_len = strlen (name);
aligned_len = ((name_len + 1 + sizeof name_len - 1)
@@ -1167,7 +1165,6 @@ exec_0 (char *name, struct exec_tracee *tracee,
offset = aligned_len - (name_len + 1);
while (offset--)
loader_area[loader_area_used++] = '\0';
#endif /* !__mips__ */
/* Close the file descriptor and return the number of bytes
used. */

2
exec/loader-aarch64.s
View File

@@ -144,7 +144,7 @@ skip_environ:
and x7, x7, -8 // align value
add x4, x7, x4 // destination argc
and x4, x4, -16 // align destination argc
// Load values that must be into registers x14-x19.
// Load values that must be preserved into registers x14-x19.
// x14 = cmd->entry
// x15 = cmd->at_entry
// x16 = cmd->at_phent

2
exec/loader-mips64el.s
View File

@@ -15,6 +15,8 @@
# You should have received a copy of the GNU General Public License
# along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
/* NOTE: this file is presently non-functional. */
include(`config-mips.m4')
.set noreorder # delay slots managed by hand

304
exec/loader-mipsel.s
View File

@@ -17,32 +17,32 @@
include(`config-mips.m4')
# Make sure not to use t4 through t7, in order to maintain portability
# with N32 ABI systems.
## Beware: $t0-$t4 alias the syscall (and function, but they are not
## material in this context) argument registers on N32 systems, and
## mustn't be relied upon to hold arguments to `SYSCALL'.
.set noreorder # delay slots managed by hand
.section .text
.global __start
__start:
dnl li $v0, SYSCALL_nanosleep # SYS_nanosleep
dnl la $a0, .timespec # rqtp
dnl li $a1, 0 # rmtp
dnl syscall # syscall
## li $v0, SYSCALL_nanosleep # SYS_nanosleep
## la $a0, timespec # rqtp
## li $a1, 0 # rmtp
## syscall # syscall
lw $s6, ($sp) # original stack pointer
addi $s0, $sp, 8 # start of load area
addi $sp, -8 # primary fd, secondary fd
li $t0, -1 # secondary fd
sw $t0, 4($sp) # initialize secondary fd
.next_action:
next_action:
lw $s2, ($s0) # action number
nop # delay slot
andi $t0, $s2, 15 # t0 = s2 & 15
beqz $t0, .open_file # open file?
beqz $t0, open_file # open file?
li $t1, 3 # t1 = 3, delay slot
beq $t0, $t1, .rest_of_exec # jump to code
beq $t0, $t1, rest_of_exec # jump to code
li $t1, 4 # t1 = 4, delay slot
beq $t0, $t1, .do_mmap_anon # anonymous mmap
.do_mmap:
beq $t0, $t1, do_mmap_anon # anonymous mmap
do_mmap:
lw $a0, 4($s0) # vm_address, delay slot
lw $v1, 8($s0) # file_offset
lw $a2, 12($s0) # protection
@@ -50,33 +50,33 @@ dnl syscall # syscall
lw $a3, 20($s0) # flags
lw $v0, ($sp) # primary fd
andi $t1, $s2, 16 # t1 = s2 & 16
beqz $t1, .do_mmap_1 # secondary fd?
beqz $t1, do_mmap_1 # secondary fd?
nop # delay slot
lw $v0, 4($sp) # secondary fd
nop # delay slot
.do_mmap_1:
do_mmap_1:
SYSCALL(`$v0',`$v1',`$zero',`$zero') # syscall args
li $v0, SYSCALL_mmap # SYS_mmap
syscall # syscall
bne $a3, $zero, .perror # perror
bnez $a3, perror # perror
RESTORE() # delay slot, restore sp
lw $s5, 24($s0) # clear
add $t0, $a0, $a1 # t0 = length + vm_address, delay slot
sub $t1, $t0, $s5 # t1 = t0 - clear
.align:
beq $t0, $t1, .continue # already finished?
align:
beq $t0, $t1, continue # already finished?
nop # delay slot
andi $t2, $t1, 3 # t1 & 3?
bnez $t2, .fillw # start filling longs
bnez $t2, fillw # start filling longs
nop # delay slot
sb $zero, ($t1) # clear byte
addi $t1, $t1, 1 # t1++
j .align # continue
j align # continue
nop # delay slot
.fillw:
fillw:
sub $t2, $t0, $t1 # t2 = t0 - t1
sltiu $t2, $t2, 32 # r2 < 32?
bne $t2, $zero, .fillb # fill bytes
bne $t2, $zero, fillb # fill bytes
nop # delay slot
sw $zero, ($t1) # zero word
addi $t1, $t1, 4 # next word
@@ -94,53 +94,52 @@ RESTORE() # delay slot, restore sp
addi $t1, $t1, 4 # next word
sw $zero, ($t1) # zero word
addi $t1, $t1, 4 # next word
j .fillw # fill either word or byte
j fillw # fill either word or byte
nop # delay slot
.fillb:
beq $t0, $t1, .continue # already finished?
fillb:
beq $t0, $t1, continue # already finished?
nop # delay slot
sb $zero, ($t1) # clear byte
addi $t1, $t1, 1 # t1++
.continue:
continue:
addi $s0, $s0, 28 # s0 = next action
j .next_action # next action
j next_action # next action
nop # delay slot
.do_mmap_anon:
do_mmap_anon:
lw $v1, 8($s0) # file_offset
lw $a2, 12($s0) # protection
lw $a1, 16($s0) # length
lw $a3, 20($s0) # flags
li $t4, -1 # fd
j .do_mmap_1 # do mmap
nop # delay slot
.open_file:
j do_mmap_1 # do mmap
li $v0, -1 # fd, delay slot
open_file:
li $v0, SYSCALL_open # SYS_open
addi $a0, $s0, 4 # start of name
move $a1, $zero # flags = O_RDONLY
move $a2, $zero # mode = 0
syscall # syscall
bne $a3, $zero, .perror # perror
bne $a3, $zero, perror # perror
addi $s0, $s0, 4 # start of string, delay slot
move $t3, $s0 # t3 = char past separator
.nextc:
nextc:
lb $t0, ($s0) # load byte
addi $s0, $s0, 1 # s0++
li $t1, 47 # directory separator `/'
bne $t0, $t1, .nextc1 # is separator char?
bne $t0, $t1, nextc1 # is separator char?
nop # delay slot
move $t3, $s0 # t3 = char past separator
.nextc1:
bnez $t0, .nextc # next character?
nextc1:
bnez $t0, nextc # next character?
nop # delay slot
addi $s0, $s0, 3 # adjust for round
li $t2, -4 # t2 = -4
and $s0, $s0, $t2 # mask for round
andi $t0, $s2, 16 # t1 = s2 & 16
beqz $t0, .primary # primary fd?
beqz $t0, primary # primary fd?
move $t0, $sp # address of primary fd, delay slot
addi $t0, $t0, 4 # address of secondary fd
j .next_action # next action
.primary:
j next_action # next action
primary:
sw $v0, ($t0) # store fd, delay slot
li $v0, SYSCALL_prctl # SYS_prctl
li $a0, 15 # PR_SET_NAME
@@ -150,86 +149,209 @@ RESTORE() # delay slot, restore sp
SYSCALL(`$a2',`$a2',`$a2',`$a2') # syscall args
syscall # syscall
RESTORE() # restore sp
j .next_action # next action
j next_action # next action
nop # delay slot
.perror:
perror:
move $a0, $v0 # errno
li $v0, SYSCALL_exit # SYS_exit
syscall # syscall
.rest_of_exec:
rest_of_exec:
move $s1, $s6 # s1 = original SP
lw $t0, ($s1) # argc
nop # delay slot
sll $t0, $t0, 2 # argc *= 4
addi $t0, $t0, 8 # argc += 8
add $s1, $s1, $t0 # s1 = start of envp
.skipenv:
lw $t0, ($s1) # t0 = *s1
skip_environ:
/* Locate the auxiliary vector. */
1: lw $t0, ($s1) # t0 = *s1
bnez $t0, 1b # skip environment entry
addi $s1, $s1, 4 # s1++
bne $t0, $zero, .skipenv # skip again
nop # delay slot
la $s2, .auxvtab # address of auxv table
.one_auxv:
lw $t0, ($s1) # t0 = auxv type
li $t1, 10 # t1 = 10, delay slot
beqz $t0, .finish # is AT_IGNORE?
sltu $t1, $t0, $t1 # t1 = t0 < num offsets, delay slot
beq $t1, $zero, .next # next auxv
sll $t1, $t0, 2 # t1 = t0 * 4, delay slot
add $t1, $s2, $t1 # t1 = .auxvtab + t1
lw $t2, ($t1) # t2 = *t1
nop # delay slot
beqz $t2, .next # skip auxv
add $t2, $s0, $t2 # t2 = s0 + t2
lw $t2, ($t2) # t2 = *t2
nop # delay slot
sw $t2, 4($s1) # set auxv value
.next:
addi $s1, $s1, 8 # next auxv
j .one_auxv # next auxv
nop # delay slot
.finish:
lw $t0, 4($sp) # secondary fd
lw $s1, ($sp) # primary fd, delay slot, preserved
move $s2, $s1 # $s2 = end of environment
1: lw $t0, ($s1) # t0 = *s1
bnez $t0, 1b # skip auxiliary vector entry
addi $s1, $s1, 8 # (Elf32_auxv_t *) s1++
/* Decide how many bytes must be copied and where to
save the file name. Move the stack pointer to a safe
position below any data that must be preserved. */
lw $t1, 32($s0) # length of string
addi $t1, $t1, 1
addi $t2, $s0, 36 # pointer to string
sub $t3, $s1, $s6 # number of bytes in vectors
sub $t0, $s1, $t1 # position of string
and $t0, $t0, -16 # align value
sub $t3, $t0, $t3 # position of argc
and $t3, $t3, -16 # align value
/* Move the stack pointer and save required information.
4(FP) = secondary/interpreter fd.
0(FP) = primary/executable fd.
-4(FP) = cmd->entry
-8(FP) = cmd->at_entry
-12(FP) = cmd->at_phent
-16(FP) = cmd->at_phnum
-20(FP) = cmd->at_phdr
-24(FP) = cmd->at_base
-28(FP) = cmd->fpu_mode (only significant when N32)
$sp = copy of string. */
move $t4, $sp # current sp
sub $t5, $t3, $sp # new argc - current sp
bleu $t5, -8, 1f # more than two slots apart
addi $sp, $t3, -8 # $sp = two slots below new argc
j 2f # skip copying fds
1: move $sp, $t4 # retain current sp
lw $t5, ($t4) # old primary fd
sw $t5, ($sp) # save the same
lw $t5, 4($t4) # old interpreter fd
sw $t5, 4($sp) # save the same
2: move FP, $sp # set base pointer
addi $sp, $sp, -28 # command data
lw $t5, 4($s0) # entry
lw $t6, 8($s0) # at_entry
sw $t5, -4(FP) # save entry
sw $t6, -8(FP) # save at_entry
lw $t5, 12($s0) # at_phent
lw $t6, 16($s0) # at_phnum
sw $t5, -12(FP) # save at_phent
sw $t6, -16(FP) # save at_phnum
lw $t5, 20($s0) # at_phdr
lw $t6, 24($s0) # at_base
sw $t5, -20(FP) # save at_phdr
sw $t6, -24(FP) # save at_base
lw $t5, 28($s0) # fpu_mode
sw $t5, -28(FP) # save fpu_mode
sub $sp, $sp, $t1 # space for string
/* Save the input string. */
add $t5, $t2, $t1 # end of source ($t2)
move $t6, $sp # dst
move $s0, $t1 # $s0 = length of string
/* src = $t2, dst = $t6 */
bgeu $t2, $t5, 2f # there already?
nop
1: lb $t1, ($t2) # $t1 = *$t2
addi $t2, $t2, 1 # $t2++
addi $t6, $t6, 1 # $t6++
bltu $t2, $t5, 1b
sb $t1, -1($t6) # *($t6 - 1) = $t1
2: move $s3, $sp # copy of string
and $sp, $sp, -16 # align stack
copy_env_and_args:
/* Copy argc, argv, and the environment array.
$t4 = destination, $t5 = src, $s2 = src_end */
move $t4, $t3 # destination of argc
move $t5, $s6 # original SP
bgeu $t5, $s2, 2f # there already?
nop
1: lw $t1, ($t5) # $t1 = *src
addi $t5, $t5, 4 # src++
addi $t4, $t4, 4 # dst++
bltu $t5, $s2, 1b # src < src_end
sw $t1, -4($t4) # *(dst - 4) = $t1
copy_auxv:
/* $t4 = destination, $t5 = first auxval. */
2: lw $t1, ($t5) # a_type
lw $t2, 4($t5) # a_un.a_val
addi $t4, $t4, 8 # (Elf32_auxv_t *) dst++
addi $t5, $t5, 8 # (Elf32_auxv_t *) src++
beqz $t1, 8f # AT_NULL
li $t6, 3
beq $t1, $t6, 1f # AT_PHDR
li $t6, 4
beq $t1, $t6, 2f # AT_PHENT
li $t6, 5
beq $t1, $t6, 3f # AT_PHNUM
li $t6, 9
beq $t1, $t6, 4f # AT_ENTRY
li $t6, 7
beq $t1, $t6, 5f # AT_BASE
li $t6, 31
beq $t1, $t6, 6f # AT_EXECFN
nop
b 7f
nop
1: b 7f
lw $t2, -20(FP)
2: b 7f
lw $t2, -12(FP)
3: b 7f
lw $t2, -16(FP)
4: b 7f
lw $t2, -8(FP)
5: b 7f
lw $t2, -24(FP)
6: b 7f
move $t2, $t0
7: sw $t1, -8($t4) # dst->a_type
j copy_auxv
sw $t2, -4($t4) # dst->a_un.a_val
/* Copy the final element. */
8: sw $t1, -8($t4) # dst->a_type
sw $t2, -4($t4) # dst->a_un.a_val
finish:
/* Copy the string to its position in auxv
(src = $s3, dst = $t0). */
add $t1, $s3, $s0 # src end
bgeu $s3, $t1, 2f # there already?
nop
1: lb $t2, ($s3) # c = *src
addi $s3, $s3, 1 # *src++
addi $t0, $t0, 1 # dst++
bltu $s3, $t1, 1b
sb $t2, -1($t0) # *(dst - 1) = c
/* Save variables. */
2: move $s6, $t3 # new stack pointer
lw $t4, 4(FP) # secondary fd
lw $s1, (FP) # primary fd, delay slot, preserved
li $t2, -1 # immediate -1
beq $t0, $t2, .finish1 # secondary fd set?
beq $t4, $t2, finish1 # secondary fd set?
li $v0, SYSCALL_close # SYS_close, delay slot
move $a0, $t0 # fd
move $a0, $t4 # fd
syscall # syscall
li $v0, SYSCALL_close # SYS_close
.finish1:
finish1:
move $a0, $s1 # primary fd
syscall # syscall
li $v0, SYSCALL_prctl # SYS_prctl
li $a0, 45 # PR_SET_FP_MODE
lw $a1, 28($s0) # fpu_mode
lw $a1, -28(FP) # fpu_mode
move $a2, $zero # arg3
move $a3, $zero # arg4
SYSCALL(`$a2',`$a2',`$a2',`$a2') # syscall args
syscall # syscall
RESTORE() # restore sp
.jump:
jump:
move $v0, $zero # rtld_fini
lw $t0, 4($s0) # entry
lw $t9, -4(FP) # entry
move $sp, $s6 # restore stack pointer, delay slot
jr $t0 # enter
/* Clear at least one page's worth of stack. glibc on mipsel
copies certain fields from the stack to the `link_map'
structure representing ld.so, which are not subsequently
replaced if otherwise than zero.
XXX: report this glibc bug? */
addi $v0, $sp, -4096
and $v0, $v0, -4095
1: sw $zero, ($v0) # copy 32 byte blocks
sw $zero, 4($v0)
sw $zero, 8($v0)
sw $zero, 12($v0)
sw $zero, 16($v0)
sw $zero, 20($v0)
sw $zero, 24($v0)
sw $zero, 28($v0)
addi $v0, $v0, 32
sub $t0, $sp, $v0 # remainder
bge $t0, 32, 1b # test remainder
nop # copy 4 byte blocks
beqz $t0, 2f
1: addi $v0, $v0, 4
bltu $v0, $sp, 1b
sw $zero, -4($v0)
2: jr $t9 # enter
nop # delay slot
.auxvtab:
.long 0 # 0
.long 0 # 1
.long 0 # 2
.long 20 # 3 AT_PHDR
.long 12 # 4 AT_PHENT
.long 16 # 5 AT_PHNUM
.long 0 # 6
.long 24 # 7 AT_BASE
.long 0 # 8
.long 8 # 9 AT_ENTRY
.timespec:
.long 10
.long 10
## timespec:
## .long 10
## .long 10
# Local Variables:
# asm-comment-char: ?#