MIPS: scall: Always run the seccomp syscall filters
The MIPS syscall handler code used to return -ENOSYS on invalid syscalls. Whilst this is expected, it caused problems for seccomp filters because the said filters never had the change to run since the code returned -ENOSYS before triggering them. This caused problems on the chromium testsuite for filters looking for invalid syscalls. This has now changed and the seccomp filters are always run even if the syscall is invalid. We return -ENOSYS once we return from the seccomp filters. Moreover, similar codepaths have been merged in the process which simplifies somewhat the overall syscall code. Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/11236/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Markos Chandras
Ralf Baechle
Родитель
66803dd919
Коммит
d218af7849
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@ -36,16 +36,8 @@ NESTED(handle_sys, PT_SIZE, sp)
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lw t1, PT_EPC(sp) # skip syscall on return
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subu v0, v0, __NR_O32_Linux # check syscall number
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sltiu t0, v0, __NR_O32_Linux_syscalls + 1
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addiu t1, 4 # skip to next instruction
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sw t1, PT_EPC(sp)
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beqz t0, illegal_syscall
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sll t0, v0, 2
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la t1, sys_call_table
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addu t1, t0
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lw t2, (t1) # syscall routine
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beqz t2, illegal_syscall
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sw a3, PT_R26(sp) # save a3 for syscall restarting
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@ -96,6 +88,16 @@ loads_done:
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li t1, _TIF_WORK_SYSCALL_ENTRY
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and t0, t1
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bnez t0, syscall_trace_entry # -> yes
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syscall_common:
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sltiu t0, v0, __NR_O32_Linux_syscalls + 1
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beqz t0, illegal_syscall
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sll t0, v0, 2
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la t1, sys_call_table
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addu t1, t0
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lw t2, (t1) # syscall routine
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beqz t2, illegal_syscall
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jalr t2 # Do The Real Thing (TM)
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@ -116,7 +118,7 @@ o32_syscall_exit:
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syscall_trace_entry:
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SAVE_STATIC
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move s0, t2
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move s0, v0
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move a0, sp
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/*
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@ -129,27 +131,18 @@ syscall_trace_entry:
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1: jal syscall_trace_enter
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bltz v0, 2f # seccomp failed? Skip syscall
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bltz v0, 1f # seccomp failed? Skip syscall
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move v0, s0 # restore syscall
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move t0, s0
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RESTORE_STATIC
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lw a0, PT_R4(sp) # Restore argument registers
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lw a1, PT_R5(sp)
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lw a2, PT_R6(sp)
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lw a3, PT_R7(sp)
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jalr t0
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j syscall_common
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li t0, -EMAXERRNO - 1 # error?
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sltu t0, t0, v0
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sw t0, PT_R7(sp) # set error flag
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beqz t0, 1f
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lw t1, PT_R2(sp) # syscall number
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negu v0 # error
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sw t1, PT_R0(sp) # save it for syscall restarting
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1: sw v0, PT_R2(sp) # result
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2: j syscall_exit
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1: j syscall_exit
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/* ------------------------------------------------------------------------ */
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@ -39,18 +39,11 @@ NESTED(handle_sys64, PT_SIZE, sp)
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.set at
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#endif
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dsubu t0, v0, __NR_64_Linux # check syscall number
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sltiu t0, t0, __NR_64_Linux_syscalls + 1
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#if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32)
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ld t1, PT_EPC(sp) # skip syscall on return
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daddiu t1, 4 # skip to next instruction
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sd t1, PT_EPC(sp)
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#endif
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beqz t0, illegal_syscall
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dsll t0, v0, 3 # offset into table
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ld t2, (sys_call_table - (__NR_64_Linux * 8))(t0)
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# syscall routine
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sd a3, PT_R26(sp) # save a3 for syscall restarting
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@ -59,6 +52,17 @@ NESTED(handle_sys64, PT_SIZE, sp)
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and t0, t1, t0
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bnez t0, syscall_trace_entry
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syscall_common:
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dsubu t2, v0, __NR_64_Linux
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sltiu t0, t2, __NR_64_Linux_syscalls + 1
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beqz t0, illegal_syscall
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dsll t0, t2, 3 # offset into table
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dla t2, sys_call_table
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daddu t0, t2, t0
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ld t2, (t0) # syscall routine
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beqz t2, illegal_syscall
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jalr t2 # Do The Real Thing (TM)
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li t0, -EMAXERRNO - 1 # error?
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@ -78,14 +82,14 @@ n64_syscall_exit:
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syscall_trace_entry:
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SAVE_STATIC
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move s0, t2
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move s0, v0
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move a0, sp
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move a1, v0
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jal syscall_trace_enter
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bltz v0, 2f # seccomp failed? Skip syscall
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bltz v0, 1f # seccomp failed? Skip syscall
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move t0, s0
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move v0, s0
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RESTORE_STATIC
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ld a0, PT_R4(sp) # Restore argument registers
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ld a1, PT_R5(sp)
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@ -93,19 +97,9 @@ syscall_trace_entry:
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ld a3, PT_R7(sp)
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ld a4, PT_R8(sp)
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ld a5, PT_R9(sp)
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jalr t0
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j syscall_common
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li t0, -EMAXERRNO - 1 # error?
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sltu t0, t0, v0
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sd t0, PT_R7(sp) # set error flag
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beqz t0, 1f
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ld t1, PT_R2(sp) # syscall number
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dnegu v0 # error
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sd t1, PT_R0(sp) # save it for syscall restarting
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1: sd v0, PT_R2(sp) # result
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2: j syscall_exit
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1: j syscall_exit
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illegal_syscall:
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/* This also isn't a 64-bit syscall, throw an error. */
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@ -52,6 +52,7 @@ NESTED(handle_sysn32, PT_SIZE, sp)
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and t0, t1, t0
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bnez t0, n32_syscall_trace_entry
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syscall_common:
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jalr t2 # Do The Real Thing (TM)
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li t0, -EMAXERRNO - 1 # error?
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@ -75,9 +76,9 @@ n32_syscall_trace_entry:
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move a1, v0
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jal syscall_trace_enter
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bltz v0, 2f # seccomp failed? Skip syscall
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bltz v0, 1f # seccomp failed? Skip syscall
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move t0, s0
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move t2, s0
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RESTORE_STATIC
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ld a0, PT_R4(sp) # Restore argument registers
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ld a1, PT_R5(sp)
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@ -85,19 +86,9 @@ n32_syscall_trace_entry:
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ld a3, PT_R7(sp)
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ld a4, PT_R8(sp)
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ld a5, PT_R9(sp)
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jalr t0
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j syscall_common
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li t0, -EMAXERRNO - 1 # error?
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sltu t0, t0, v0
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sd t0, PT_R7(sp) # set error flag
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beqz t0, 1f
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ld t1, PT_R2(sp) # syscall number
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dnegu v0 # error
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sd t1, PT_R0(sp) # save it for syscall restarting
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1: sd v0, PT_R2(sp) # result
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2: j syscall_exit
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1: j syscall_exit
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not_n32_scall:
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/* This is not an n32 compatibility syscall, pass it on to
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@ -87,6 +87,7 @@ loads_done:
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and t0, t1, t0
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bnez t0, trace_a_syscall
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syscall_common:
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jalr t2 # Do The Real Thing (TM)
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li t0, -EMAXERRNO - 1 # error?
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@ -130,9 +131,9 @@ trace_a_syscall:
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1: jal syscall_trace_enter
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bltz v0, 2f # seccomp failed? Skip syscall
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bltz v0, 1f # seccomp failed? Skip syscall
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move t0, s0
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move t2, s0
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RESTORE_STATIC
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ld a0, PT_R4(sp) # Restore argument registers
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ld a1, PT_R5(sp)
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@ -142,19 +143,9 @@ trace_a_syscall:
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ld a5, PT_R9(sp)
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ld a6, PT_R10(sp)
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ld a7, PT_R11(sp) # For indirect syscalls
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jalr t0
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j syscall_common
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li t0, -EMAXERRNO - 1 # error?
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sltu t0, t0, v0
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sd t0, PT_R7(sp) # set error flag
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beqz t0, 1f
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ld t1, PT_R2(sp) # syscall number
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dnegu v0 # error
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sd t1, PT_R0(sp) # save it for syscall restarting
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1: sd v0, PT_R2(sp) # result
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2: j syscall_exit
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1: j syscall_exit
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/* ------------------------------------------------------------------------ */
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