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sh: Rearrange blocks in entry-common.S
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This avoids out-of-range jumps that get auto-replaced by the assembler
and prepares for the changes needed to implement SECCOMP_FILTER cleanly.

Signed-off-by: Michael Karcher <[email protected]>
Tested-by: John Paul Adrian Glaubitz <[email protected]>
Signed-off-by: Rich Felker <[email protected]>
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Michael Karcher authored and Rich Felker committed Aug 15, 2020
1 parent e1cc9d8 commit 9d2ec8f
Showing 1 changed file with 29 additions and 28 deletions.
57 changes: 29 additions & 28 deletions arch/sh/kernel/entry-common.S
Original file line number Diff line number Diff line change
Expand Up @@ -178,34 +178,6 @@ syscall_exit_work:
bra resume_userspace
nop

.align 2
syscall_trace_entry:
! Yes it is traced.
mov r15, r4
mov.l 7f, r11 ! Call do_syscall_trace_enter which notifies
jsr @r11 ! superior (will chomp R[0-7])
nop
mov.l r0, @(OFF_R0,r15) ! Save return value
! Reload R0-R4 from kernel stack, where the
! parent may have modified them using
! ptrace(POKEUSR). (Note that R0-R2 are
! reloaded from the kernel stack by syscall_call
! below, so don't need to be reloaded here.)
! This allows the parent to rewrite system calls
! and args on the fly.
mov.l @(OFF_R4,r15), r4 ! arg0
mov.l @(OFF_R5,r15), r5
mov.l @(OFF_R6,r15), r6
mov.l @(OFF_R7,r15), r7 ! arg3
mov.l @(OFF_R3,r15), r3 ! syscall_nr
!
mov.l 6f, r10 ! Number of syscalls
cmp/hs r10, r3
bf syscall_call
mov #-ENOSYS, r0
bra syscall_exit
mov.l r0, @(OFF_R0,r15) ! Return value

__restore_all:
mov #OFF_SR, r0
mov.l @(r0,r15), r0 ! get status register
Expand Down Expand Up @@ -388,6 +360,35 @@ syscall_exit:
bf syscall_exit_work
bra __restore_all
nop

.align 2
syscall_trace_entry:
! Yes it is traced.
mov r15, r4
mov.l 7f, r11 ! Call do_syscall_trace_enter which notifies
jsr @r11 ! superior (will chomp R[0-7])
nop
mov.l r0, @(OFF_R0,r15) ! Save return value
! Reload R0-R4 from kernel stack, where the
! parent may have modified them using
! ptrace(POKEUSR). (Note that R0-R2 are
! reloaded from the kernel stack by syscall_call
! below, so don't need to be reloaded here.)
! This allows the parent to rewrite system calls
! and args on the fly.
mov.l @(OFF_R4,r15), r4 ! arg0
mov.l @(OFF_R5,r15), r5
mov.l @(OFF_R6,r15), r6
mov.l @(OFF_R7,r15), r7 ! arg3
mov.l @(OFF_R3,r15), r3 ! syscall_nr
!
mov.l 6f, r10 ! Number of syscalls
cmp/hs r10, r3
bf syscall_call
mov #-ENOSYS, r0
bra syscall_exit
mov.l r0, @(OFF_R0,r15) ! Return value

.align 2
#if !defined(CONFIG_CPU_SH2)
1: .long TRA
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