From ff7eace6a779b16aa8aa7e995f493d2d97e089e4 Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Wed, 17 Jul 2024 19:00:21 +0200
Subject: [PATCH] Obtain offset of sig pctl more sanely.
---
redox-rt/src/arch/x86_64.rs | 32 +++++++++++++-------------------
redox-rt/src/signal.rs | 3 ++-
2 files changed, 15 insertions(+), 20 deletions(-)
diff --git a/redox-rt/src/arch/x86_64.rs b/redox-rt/src/arch/x86_64.rs
index 9932a714..7ec67bca 100644
--- a/redox-rt/src/arch/x86_64.rs
+++ b/redox-rt/src/arch/x86_64.rs
@@ -10,7 +10,7 @@ use syscall::{
use crate::{
proc::{fork_inner, FdGuard},
- signal::{inner_c, RtSigarea, SigStack},
+ signal::{inner_c, RtSigarea, SigStack, PROC_CONTROL_STRUCT},
RtTcb, Tcb,
};
@@ -24,13 +24,11 @@ pub struct SigArea {
pub tmp_rip: usize,
pub tmp_rsp: usize,
pub tmp_rax: usize,
- pub tmp_rcx: usize,
pub tmp_rdx: usize,
pub altstack_top: usize,
pub altstack_bottom: usize,
pub disable_signals_depth: u64,
- pub pctl: usize, // TODO: find out how to correctly reference that static
pub last_sig_was_restart: bool,
}
@@ -171,13 +169,10 @@ asmfunction!(__relibc_internal_sigentry: ["
// Save some registers
mov fs:[{tcb_sa_off} + {sa_tmp_rsp}], rsp
mov fs:[{tcb_sa_off} + {sa_tmp_rax}], rax
- mov fs:[{tcb_sa_off} + {sa_tmp_rcx}], rcx
mov fs:[{tcb_sa_off} + {sa_tmp_rdx}], rdx
// First, select signal, always pick first available bit
1:
- mov rcx, fs:[{tcb_sa_off} + {sa_off_pctl}]
-
// Read standard signal word - first targeting this thread
mov rax, fs:[{tcb_sc_off} + {sc_word}]
mov rdx, rax
@@ -189,17 +184,17 @@ asmfunction!(__relibc_internal_sigentry: ["
// If no unblocked thread signal was found, check for process.
// This is competitive; we need to atomically check if *we* cleared the process-wide pending
// bit, otherwise restart.
- mov eax, [rcx + {pctl_off_pending}]
+ mov eax, [rip + {pctl} + {pctl_off_pending}]
and eax, edx
bsf eax, eax
jz 8f
- lock btr [rcx + {pctl_off_pending}], eax
+ lock btr [rip + {pctl} + {pctl_off_pending}], eax
jc 9f
8:
// Read second signal word - both process and thread simultaneously.
// This must be done since POSIX requires low realtime signals to be picked first.
mov edx, fs:[{tcb_sc_off} + {sc_word} + 8]
- mov eax, [rcx + {pctl_off_pending} + 4]
+ mov eax, [rip + {pctl} + {pctl_off_pending} + 4]
or eax, edx
and eax, fs:[{tcb_sc_off} + {sc_word} + 12]
bsf eax, eax
@@ -209,7 +204,7 @@ asmfunction!(__relibc_internal_sigentry: ["
jc 2f // then continue as usual
// otherwise, try clearing pending
- lock btr [rcx + {pctl_off_pending}], eax
+ lock btr [rip + {pctl} + {pctl_off_pending}], eax
jnc 1b
2:
mov edx, eax
@@ -223,13 +218,13 @@ asmfunction!(__relibc_internal_sigentry: ["
// By now we have selected a signal, stored in eax (6-bit). We now need to choose whether or
// not to switch to the alternate signal stack. If SA_ONSTACK is clear for this signal, then
// skip the sigaltstack logic.
- mov edx, eax
- add edx, edx
- lea rdx, [{pctl_off_actions} + edx * 8]
- add rdx, fs:[{tcb_sa_off} + {sa_off_pctl}]
+ lea rdx, [rip + {pctl} + {pctl_off_actions}]
+
+ // LEA doesn't support x16, so just do two x8s.
+ lea rdx, [rdx + 8 * rax]
+ lea rdx, [rdx + 8 * rax]
- // scale factor 16 doesn't exist, so we premultiplied edx by 2
- bt qword ptr [rdx], 58
+ bt qword ptr [rdx], {SA_ONSTACK_BIT}
jnc 4f
// Otherwise, the altstack is already active. The sigaltstack being disabled, is equivalent
@@ -363,7 +358,6 @@ __relibc_internal_sigentry_crit_second:
sa_tmp_rip = const offset_of!(SigArea, tmp_rip),
sa_tmp_rsp = const offset_of!(SigArea, tmp_rsp),
sa_tmp_rax = const offset_of!(SigArea, tmp_rax),
- sa_tmp_rcx = const offset_of!(SigArea, tmp_rcx),
sa_tmp_rdx = const offset_of!(SigArea, tmp_rdx),
sa_altstack_top = const offset_of!(SigArea, altstack_top),
sa_altstack_bottom = const offset_of!(SigArea, altstack_bottom),
@@ -374,11 +368,11 @@ __relibc_internal_sigentry_crit_second:
tcb_sc_off = const offset_of!(crate::Tcb, os_specific) + offset_of!(RtSigarea, control),
pctl_off_actions = const offset_of!(SigProcControl, actions),
pctl_off_pending = const offset_of!(SigProcControl, pending),
- //pctl = sym PROC_CONTROL_STRUCT,
- sa_off_pctl = const offset_of!(SigArea, pctl),
+ pctl = sym PROC_CONTROL_STRUCT,
supports_avx = sym SUPPORTS_AVX,
REDZONE_SIZE = const 128,
STACK_ALIGN = const 16,
+ SA_ONSTACK_BIT = const 58, // (1 << 58) >> 32 = 0x0400_0000
]);
extern "C" {
diff --git a/redox-rt/src/signal.rs b/redox-rt/src/signal.rs
index 04b1ffdd..0b092cd1 100644
--- a/redox-rt/src/signal.rs
+++ b/redox-rt/src/signal.rs
@@ -473,7 +473,8 @@ pub fn setup_sighandler(tcb: &RtTcb) {
// equivalent to not using any altstack at all (the default).
arch.altstack_top = usize::MAX;
arch.altstack_bottom = 0;
- #[cfg(not(target_arch = "x86"))]
+ // TODO
+ #[cfg(target_arch = "aarch64")]
{
arch.pctl = core::ptr::addr_of!(PROC_CONTROL_STRUCT) as usize;
}
--
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