Date: Fri, 17 Jun 2022 19:38:15 GMT From: Dmitry Chagin <dchagin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: e5a000ff5afa - stable/13 - linux: make PTRACE_GETREGS return correct struct Message-ID: <202206171938.25HJcFhx014447@gitrepo.freebsd.org>
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The branch stable/13 has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=e5a000ff5afa8b8e4043284f2419b4042d06667c commit e5a000ff5afa8b8e4043284f2419b4042d06667c Author: Edward Tomasz Napierala <trasz@FreeBSD.org> AuthorDate: 2021-10-29 15:18:13 +0000 Commit: Dmitry Chagin <dchagin@FreeBSD.org> CommitDate: 2022-06-17 19:33:34 +0000 linux: make PTRACE_GETREGS return correct struct Previously it returned a shorter struct. I can't find any modern software that uses it, but tests/ptrace from strace(1) repo complained. Differential Revision: https://reviews.freebsd.org/D32601 (cherry picked from commit ad0379660d0c77aaf0ca6ec19472b7bb173c5794) --- sys/amd64/linux/linux_ptrace.c | 62 ++++++++++++------------------------------ 1 file changed, 18 insertions(+), 44 deletions(-) diff --git a/sys/amd64/linux/linux_ptrace.c b/sys/amd64/linux/linux_ptrace.c index 770ebcf58364..ecfe2f7b5818 100644 --- a/sys/amd64/linux/linux_ptrace.c +++ b/sys/amd64/linux/linux_ptrace.c @@ -214,38 +214,6 @@ struct syscall_info { }; }; -/* - * Translate amd64 ptrace registers between Linux and FreeBSD formats. - * The translation is pretty straighforward, for all registers but - * orig_rax on Linux side and r_trapno and r_err in FreeBSD. - */ -static void -map_regs_to_linux(struct reg *b_reg, struct linux_pt_reg *l_reg) -{ - - l_reg->r15 = b_reg->r_r15; - l_reg->r14 = b_reg->r_r14; - l_reg->r13 = b_reg->r_r13; - l_reg->r12 = b_reg->r_r12; - l_reg->rbp = b_reg->r_rbp; - l_reg->rbx = b_reg->r_rbx; - l_reg->r11 = b_reg->r_r11; - l_reg->r10 = b_reg->r_r10; - l_reg->r9 = b_reg->r_r9; - l_reg->r8 = b_reg->r_r8; - l_reg->rax = b_reg->r_rax; - l_reg->rcx = b_reg->r_rcx; - l_reg->rdx = b_reg->r_rdx; - l_reg->rsi = b_reg->r_rsi; - l_reg->rdi = b_reg->r_rdi; - l_reg->orig_rax = b_reg->r_rax; - l_reg->rip = b_reg->r_rip; - l_reg->cs = b_reg->r_cs; - l_reg->eflags = b_reg->r_rflags; - l_reg->rsp = b_reg->r_rsp; - l_reg->ss = b_reg->r_ss; -} - static void map_regs_from_linux(struct reg *b_reg, struct linux_pt_reg *l_reg) { @@ -434,14 +402,21 @@ linux_ptrace_getregs(struct thread *td, pid_t pid, void *data) { struct ptrace_lwpinfo lwpinfo; struct reg b_reg; - struct linux_pt_reg l_reg; + struct linux_pt_regset l_regset; + struct pcb *pcb; int error; error = kern_ptrace(td, PT_GETREGS, pid, &b_reg, 0); if (error != 0) return (error); - map_regs_to_linux(&b_reg, &l_reg); + pcb = td->td_pcb; + if (td == curthread) + update_pcb_bases(pcb); + + bsd_to_linux_regset(&b_reg, &l_regset); + l_regset.fs_base = pcb->pcb_fsbase; + l_regset.gs_base = pcb->pcb_gsbase; error = kern_ptrace(td, PT_LWPINFO, pid, &lwpinfo, sizeof(lwpinfo)); if (error != 0) { @@ -450,21 +425,20 @@ linux_ptrace_getregs(struct thread *td, pid_t pid, void *data) } if (lwpinfo.pl_flags & PL_FLAG_SCE) { /* - * The strace(1) utility depends on RAX being set to -ENOSYS - * on syscall entry; otherwise it loops printing those: - * - * [ Process PID=928 runs in 64 bit mode. ] - * [ Process PID=928 runs in x32 mode. ] + * Undo the mangling done in exception.S:fast_syscall_common(). */ - l_reg.rax = -38; /* -ENOSYS */ - + l_regset.r10 = l_regset.rcx; + } + if (lwpinfo.pl_flags & (PL_FLAG_SCE | PL_FLAG_SCX)) { /* - * Undo the mangling done in exception.S:fast_syscall_common(). + * In Linux, the syscall number - passed to the syscall + * as rax - is preserved in orig_rax; rax gets overwritten + * with syscall return value. */ - l_reg.r10 = l_reg.rcx; + l_regset.orig_rax = lwpinfo.pl_syscall_code; } - error = copyout(&l_reg, (void *)data, sizeof(l_reg)); + error = copyout(&l_regset, (void *)data, sizeof(l_regset)); return (error); }
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