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Fix linux-raw inline asm for thumb-mode. (#416)
* Fix linux-raw inline asm for thumb-mode. In thumb-mode, r7 is reserved as the frame pointer and isn't permitted as an inline asm operand. It's still the syscall-number operand in syscalls though, so pass the syscall-number operand in in a separate register, copy it into r7 inside the inline asm, and then restore the value of r7 when we're done. * Add a thumbv7neon-unknown-linux-gnueabihf line to CI.
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3 files changed

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‎.github/workflows/main.yml

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@@ -163,8 +163,10 @@ jobs:
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rustup target add
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x86_64-unknown-redox
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wasm32-wasi
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thumbv7neon-unknown-linux-gnueabihf
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- run: cargo check --workspace --release -vv --target=x86_64-unknown-redox --features=all-apis
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- run: cargo check --workspace --release -vv --target=wasm32-wasi --features=all-apis
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- run: cargo check --workspace --release -vv --target=thumbv7neon-unknown-linux-gnueabihf --features=all-apis
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check_tier3:
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name: Check selected Tier 3 platforms

‎src/backend/linux_raw/arch/inline/mod.rs

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@@ -5,7 +5,14 @@
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//! conventions are otherwise the compiler's job. But for now, use inline asm.
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#[cfg_attr(target_arch = "aarch64", path = "aarch64.rs")]
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#[cfg_attr(target_arch = "arm", path = "arm.rs")]
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#[cfg_attr(
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all(target_arch = "arm", not(target_feature = "thumb-mode")),
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path = "arm.rs"
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)]
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#[cfg_attr(
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all(target_arch = "arm", target_feature = "thumb-mode"),
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path = "thumb.rs"
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)]
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#[cfg_attr(target_arch = "mips", path = "mips.rs")]
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#[cfg_attr(target_arch = "mips64", path = "mips64.rs")]
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#[cfg_attr(target_arch = "powerpc64", path = "powerpc64.rs")]

‎src/backend/linux_raw/arch/inline/thumb.rs

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@@ -0,0 +1,322 @@
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//! arm Linux system calls, using thumb-mode.
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//!
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//! In thumb-mode, r7 is the frame pointer and is not permitted to be used in
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//! an inline asm operand, so we have to use a different register and copy it
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//! into r7 inside the inline asm.
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use crate::backend::reg::{
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ArgReg, FromAsm, RetReg, SyscallNumber, ToAsm, A0, A1, A2, A3, A4, A5, R0,
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};
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use core::arch::asm;
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#[inline]
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pub(in crate::backend) unsafe fn syscall0_readonly(nr: SyscallNumber<'_>) -> RetReg<R0> {
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let r0;
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asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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lateout("r0") r0,
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options(nostack, preserves_flags, readonly)
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);
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FromAsm::from_asm(r0)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall1(nr: SyscallNumber<'_>, a0: ArgReg<'_, A0>) -> RetReg<R0> {
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let r0;
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asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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inlateout("r0") a0.to_asm() => r0,
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options(nostack, preserves_flags)
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);
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FromAsm::from_asm(r0)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall1_readonly(
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nr: SyscallNumber<'_>,
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a0: ArgReg<'_, A0>,
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) -> RetReg<R0> {
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let r0;
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asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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inlateout("r0") a0.to_asm() => r0,
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options(nostack, preserves_flags, readonly)
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);
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FromAsm::from_asm(r0)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall1_noreturn(nr: SyscallNumber<'_>, a0: ArgReg<'_, A0>) -> ! {
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asm!(
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"mov r7, {nr}",
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"svc 0",
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nr = in(reg) nr.to_asm(),
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in("r0") a0.to_asm(),
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options(noreturn)
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)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall2(
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nr: SyscallNumber<'_>,
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a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
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) -> RetReg<R0> {
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let r0;
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asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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options(nostack, preserves_flags)
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);
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FromAsm::from_asm(r0)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall2_readonly(
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nr: SyscallNumber<'_>,
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a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
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) -> RetReg<R0> {
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let r0;
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asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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options(nostack, preserves_flags, readonly)
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);
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FromAsm::from_asm(r0)
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}
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#[inline]
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pub(in crate::backend) unsafe fn syscall3(
118+
nr: SyscallNumber<'_>,
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a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
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a2: ArgReg<'_, A2>,
122+
) -> RetReg<R0> {
123+
let r0;
124+
asm!(
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"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
131+
inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
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options(nostack, preserves_flags)
135+
);
136+
FromAsm::from_asm(r0)
137+
}
138+
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#[inline]
140+
pub(in crate::backend) unsafe fn syscall3_readonly(
141+
nr: SyscallNumber<'_>,
142+
a0: ArgReg<'_, A0>,
143+
a1: ArgReg<'_, A1>,
144+
a2: ArgReg<'_, A2>,
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) -> RetReg<R0> {
146+
let r0;
147+
asm!(
148+
"mov {tmp}, r7",
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"mov r7, {nr}",
150+
"svc 0",
151+
"mov r7, {tmp}",
152+
nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
154+
inlateout("r0") a0.to_asm() => r0,
155+
in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
157+
options(nostack, preserves_flags, readonly)
158+
);
159+
FromAsm::from_asm(r0)
160+
}
161+
162+
#[inline]
163+
pub(in crate::backend) unsafe fn syscall4(
164+
nr: SyscallNumber<'_>,
165+
a0: ArgReg<'_, A0>,
166+
a1: ArgReg<'_, A1>,
167+
a2: ArgReg<'_, A2>,
168+
a3: ArgReg<'_, A3>,
169+
) -> RetReg<R0> {
170+
let r0;
171+
asm!(
172+
"mov {tmp}, r7",
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"mov r7, {nr}",
174+
"svc 0",
175+
"mov r7, {tmp}",
176+
nr = in(reg) nr.to_asm(),
177+
tmp = out(reg) _,
178+
inlateout("r0") a0.to_asm() => r0,
179+
in("r1") a1.to_asm(),
180+
in("r2") a2.to_asm(),
181+
in("r3") a3.to_asm(),
182+
options(nostack, preserves_flags)
183+
);
184+
FromAsm::from_asm(r0)
185+
}
186+
187+
#[inline]
188+
pub(in crate::backend) unsafe fn syscall4_readonly(
189+
nr: SyscallNumber<'_>,
190+
a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
192+
a2: ArgReg<'_, A2>,
193+
a3: ArgReg<'_, A3>,
194+
) -> RetReg<R0> {
195+
let r0;
196+
asm!(
197+
"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
200+
"mov r7, {tmp}",
201+
nr = in(reg) nr.to_asm(),
202+
tmp = out(reg) _,
203+
inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
206+
in("r3") a3.to_asm(),
207+
options(nostack, preserves_flags, readonly)
208+
);
209+
FromAsm::from_asm(r0)
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}
211+
212+
#[inline]
213+
pub(in crate::backend) unsafe fn syscall5(
214+
nr: SyscallNumber<'_>,
215+
a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
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a2: ArgReg<'_, A2>,
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a3: ArgReg<'_, A3>,
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a4: ArgReg<'_, A4>,
220+
) -> RetReg<R0> {
221+
let r0;
222+
asm!(
223+
"mov {tmp}, r7",
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"mov r7, {nr}",
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"svc 0",
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"mov r7, {tmp}",
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nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
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inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
232+
in("r3") a3.to_asm(),
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in("r4") a4.to_asm(),
234+
options(nostack, preserves_flags)
235+
);
236+
FromAsm::from_asm(r0)
237+
}
238+
239+
#[inline]
240+
pub(in crate::backend) unsafe fn syscall5_readonly(
241+
nr: SyscallNumber<'_>,
242+
a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
244+
a2: ArgReg<'_, A2>,
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a3: ArgReg<'_, A3>,
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a4: ArgReg<'_, A4>,
247+
) -> RetReg<R0> {
248+
let r0;
249+
asm!(
250+
"mov {tmp}, r7",
251+
"mov r7, {nr}",
252+
"svc 0",
253+
"mov r7, {tmp}",
254+
nr = in(reg) nr.to_asm(),
255+
tmp = out(reg) _,
256+
inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
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in("r3") a3.to_asm(),
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in("r4") a4.to_asm(),
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options(nostack, preserves_flags, readonly)
262+
);
263+
FromAsm::from_asm(r0)
264+
}
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#[inline]
267+
pub(in crate::backend) unsafe fn syscall6(
268+
nr: SyscallNumber<'_>,
269+
a0: ArgReg<'_, A0>,
270+
a1: ArgReg<'_, A1>,
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a2: ArgReg<'_, A2>,
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a3: ArgReg<'_, A3>,
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a4: ArgReg<'_, A4>,
274+
a5: ArgReg<'_, A5>,
275+
) -> RetReg<R0> {
276+
let r0;
277+
asm!(
278+
"mov {tmp}, r7",
279+
"mov r7, {nr}",
280+
"svc 0",
281+
"mov r7, {tmp}",
282+
nr = in(reg) nr.to_asm(),
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tmp = out(reg) _,
284+
inlateout("r0") a0.to_asm() => r0,
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in("r1") a1.to_asm(),
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in("r2") a2.to_asm(),
287+
in("r3") a3.to_asm(),
288+
in("r4") a4.to_asm(),
289+
in("r5") a5.to_asm(),
290+
options(nostack, preserves_flags)
291+
);
292+
FromAsm::from_asm(r0)
293+
}
294+
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#[inline]
296+
pub(in crate::backend) unsafe fn syscall6_readonly(
297+
nr: SyscallNumber<'_>,
298+
a0: ArgReg<'_, A0>,
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a1: ArgReg<'_, A1>,
300+
a2: ArgReg<'_, A2>,
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a3: ArgReg<'_, A3>,
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a4: ArgReg<'_, A4>,
303+
a5: ArgReg<'_, A5>,
304+
) -> RetReg<R0> {
305+
let r0;
306+
asm!(
307+
"mov {tmp}, r7",
308+
"mov r7, {nr}",
309+
"svc 0",
310+
"mov r7, {tmp}",
311+
nr = in(reg) nr.to_asm(),
312+
tmp = out(reg) _,
313+
inlateout("r0") a0.to_asm() => r0,
314+
in("r1") a1.to_asm(),
315+
in("r2") a2.to_asm(),
316+
in("r3") a3.to_asm(),
317+
in("r4") a4.to_asm(),
318+
in("r5") a5.to_asm(),
319+
options(nostack, preserves_flags, readonly)
320+
);
321+
FromAsm::from_asm(r0)
322+
}

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