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[src/trunk]: src/sys/arch/amd64/amd64 Restore the ability to debug a 32 bit p...
details: https://anonhg.NetBSD.org/src/rev/e16eb66c7531
branches: trunk
changeset: 457788:e16eb66c7531
user: christos <christos%NetBSD.org@localhost>
date: Sat Jul 20 18:25:11 2019 +0000
description:
Restore the ability to debug a 32 bit process from a 64 bit debugger:
- add a function to validate a 64 bit context in 32 bit mode to write registers
- remove 32 bit checks from read and write register functions
- check for pc to fit in 32 bits.
proposed in tech-kern, ok maxv.
diffstat:
sys/arch/amd64/amd64/netbsd32_machdep.c | 28 +++++-
sys/arch/amd64/amd64/process_machdep.c | 140 +++++++++++++++----------------
2 files changed, 92 insertions(+), 76 deletions(-)
diffs (truncated from 304 to 300 lines):
diff -r e2d6b10ca7de -r e16eb66c7531 sys/arch/amd64/amd64/netbsd32_machdep.c
--- a/sys/arch/amd64/amd64/netbsd32_machdep.c Sat Jul 20 18:23:05 2019 +0000
+++ b/sys/arch/amd64/amd64/netbsd32_machdep.c Sat Jul 20 18:25:11 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: netbsd32_machdep.c,v 1.124 2019/06/26 12:30:12 mgorny Exp $ */
+/* $NetBSD: netbsd32_machdep.c,v 1.125 2019/07/20 18:25:11 christos Exp $ */
/*
* Copyright (c) 2001 Wasabi Systems, Inc.
@@ -36,7 +36,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.124 2019/06/26 12:30:12 mgorny Exp $");
+__KERNEL_RCSID(0, "$NetBSD: netbsd32_machdep.c,v 1.125 2019/07/20 18:25:11 christos Exp $");
#ifdef _KERNEL_OPT
#include "opt_compat_netbsd.h"
@@ -382,7 +382,7 @@
regs->r_esp = tf->tf_rsp & 0xffffffff;
regs->r_ss = tf->tf_ss & 0xffff;
- return (0);
+ return 0;
}
int
@@ -987,6 +987,25 @@
return 0;
}
+static int
+cpu_mcontext32from64_validate(struct lwp *l, const struct reg *regp)
+{
+ mcontext32_t mc;
+ __greg32_t *gr32 = mc.__gregs;
+ const __greg_t *gr = regp->regs;
+
+ memset(&mc, 0, sizeof(mc));
+ gr32[_REG32_EFL] = gr[_REG_RFLAGS];
+ gr32[_REG32_EIP] = gr[_REG_RIP];
+ gr32[_REG32_CS] = gr[_REG_CS];
+ gr32[_REG32_DS] = gr[_REG_DS];
+ gr32[_REG32_ES] = gr[_REG_ES];
+ gr32[_REG32_FS] = gr[_REG_FS];
+ gr32[_REG32_GS] = gr[_REG_GS];
+ gr32[_REG32_SS] = gr[_REG_SS];
+ return cpu_mcontext32_validate(l, &mc);
+}
+
vaddr_t
netbsd32_vm_default_addr(struct proc *p, vaddr_t base, vsize_t sz,
int topdown)
@@ -1009,6 +1028,8 @@
{
MODULE_HOOK_SET(netbsd32_machine32_hook, "mach32", netbsd32_machine32);
+ MODULE_HOOK_SET(netbsd32_reg_validate_hook,
+ "mcontext32from64_validate", cpu_mcontext32from64_validate);
}
void
@@ -1016,4 +1037,5 @@
{
MODULE_HOOK_UNSET(netbsd32_machine32_hook);
+ MODULE_HOOK_UNSET(netbsd32_reg_validate_hook);
}
diff -r e2d6b10ca7de -r e16eb66c7531 sys/arch/amd64/amd64/process_machdep.c
--- a/sys/arch/amd64/amd64/process_machdep.c Sat Jul 20 18:23:05 2019 +0000
+++ b/sys/arch/amd64/amd64/process_machdep.c Sat Jul 20 18:25:11 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: process_machdep.c,v 1.41 2019/06/27 01:59:30 christos Exp $ */
+/* $NetBSD: process_machdep.c,v 1.42 2019/07/20 18:25:11 christos Exp $ */
/*
* Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
@@ -74,7 +74,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: process_machdep.c,v 1.41 2019/06/27 01:59:30 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: process_machdep.c,v 1.42 2019/07/20 18:25:11 christos Exp $");
#include "opt_xen.h"
#include <sys/param.h>
@@ -83,6 +83,7 @@
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/ptrace.h>
+#include <sys/compat_stub.h>
#include <uvm/uvm_extern.h>
@@ -103,42 +104,48 @@
}
int
-process_read_regs(struct lwp *l, struct reg *regs)
+process_read_regs(struct lwp *l, struct reg *regp)
{
struct trapframe *tf = process_frame(l);
- struct proc *p = l->l_proc;
-
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
+ long *regs = regp->regs;
+ const bool pk32 = (l->l_proc->p_flag & PK_32) != 0;
- regs->regs[_REG_RDI] = tf->tf_rdi;
- regs->regs[_REG_RSI] = tf->tf_rsi;
- regs->regs[_REG_RDX] = tf->tf_rdx;
- regs->regs[_REG_R10] = tf->tf_r10;
- regs->regs[_REG_R8] = tf->tf_r8;
- regs->regs[_REG_R9] = tf->tf_r9;
+ regs[_REG_RDI] = tf->tf_rdi;
+ regs[_REG_RSI] = tf->tf_rsi;
+ regs[_REG_RDX] = tf->tf_rdx;
+ regs[_REG_R10] = tf->tf_r10;
+ regs[_REG_R8] = tf->tf_r8;
+ regs[_REG_R9] = tf->tf_r9;
/* argX not touched */
- regs->regs[_REG_RCX] = tf->tf_rcx;
- regs->regs[_REG_R11] = tf->tf_r11;
- regs->regs[_REG_R12] = tf->tf_r12;
- regs->regs[_REG_R13] = tf->tf_r13;
- regs->regs[_REG_R14] = tf->tf_r14;
- regs->regs[_REG_R15] = tf->tf_r15;
- regs->regs[_REG_RBP] = tf->tf_rbp;
- regs->regs[_REG_RBX] = tf->tf_rbx;
- regs->regs[_REG_RAX] = tf->tf_rax;
- regs->regs[_REG_GS] = 0;
- regs->regs[_REG_FS] = 0;
- regs->regs[_REG_ES] = GSEL(GUDATA_SEL, SEL_UPL);
- regs->regs[_REG_DS] = GSEL(GUDATA_SEL, SEL_UPL);
- regs->regs[_REG_TRAPNO] = tf->tf_trapno;
- regs->regs[_REG_ERR] = tf->tf_err;
- regs->regs[_REG_RIP] = tf->tf_rip;
- regs->regs[_REG_CS] = LSEL(LUCODE_SEL, SEL_UPL);
- regs->regs[_REG_RFLAGS] = tf->tf_rflags;
- regs->regs[_REG_RSP] = tf->tf_rsp;
- regs->regs[_REG_SS] = LSEL(LUDATA_SEL, SEL_UPL);
+ regs[_REG_RCX] = tf->tf_rcx;
+ regs[_REG_R11] = tf->tf_r11;
+ regs[_REG_R12] = tf->tf_r12;
+ regs[_REG_R13] = tf->tf_r13;
+ regs[_REG_R14] = tf->tf_r14;
+ regs[_REG_R15] = tf->tf_r15;
+ regs[_REG_RBP] = tf->tf_rbp;
+ regs[_REG_RBX] = tf->tf_rbx;
+ regs[_REG_RAX] = tf->tf_rax;
+ if (pk32) {
+ regs[_REG_GS] = tf->tf_gs & 0xffff;
+ regs[_REG_FS] = tf->tf_fs & 0xffff;
+ regs[_REG_ES] = tf->tf_es & 0xffff;
+ regs[_REG_DS] = tf->tf_ds & 0xffff;
+ regs[_REG_CS] = tf->tf_cs & 0xffff;
+ regs[_REG_SS] = tf->tf_ss & 0xffff;
+ } else {
+ regs[_REG_GS] = 0;
+ regs[_REG_FS] = 0;
+ regs[_REG_ES] = GSEL(GUDATA_SEL, SEL_UPL);
+ regs[_REG_DS] = GSEL(GUDATA_SEL, SEL_UPL);
+ regs[_REG_CS] = LSEL(LUCODE_SEL, SEL_UPL);
+ regs[_REG_SS] = LSEL(LUDATA_SEL, SEL_UPL);
+ }
+ regs[_REG_TRAPNO] = tf->tf_trapno;
+ regs[_REG_ERR] = tf->tf_err;
+ regs[_REG_RIP] = tf->tf_rip;
+ regs[_REG_RFLAGS] = tf->tf_rflags;
+ regs[_REG_RSP] = tf->tf_rsp;
return 0;
}
@@ -146,11 +153,6 @@
int
process_read_fpregs(struct lwp *l, struct fpreg *regs, size_t *sz)
{
- struct proc *p = l->l_proc;
-
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
process_read_fpregs_xmm(l, ®s->fxstate);
@@ -160,11 +162,6 @@
int
process_read_dbregs(struct lwp *l, struct dbreg *regs, size_t *sz)
{
- struct proc *p = l->l_proc;
-
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
x86_dbregs_read(l, regs);
@@ -175,19 +172,20 @@
process_write_regs(struct lwp *l, const struct reg *regp)
{
struct trapframe *tf = process_frame(l);
- struct proc *p = l->l_proc;
int error;
const long *regs = regp->regs;
-
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
+ const bool pk32 = (l->l_proc->p_flag & PK_32) != 0;
/*
* Check for security violations. Note that struct regs is compatible
* with the __gregs array in mcontext_t.
*/
- error = cpu_mcontext_validate(l, (const mcontext_t *)regs);
+ if (pk32) {
+ MODULE_HOOK_CALL(netbsd32_reg_validate_hook, (l, regp), EINVAL,
+ error);
+ } else {
+ error = cpu_mcontext_validate(l, (const mcontext_t *)regs);
+ }
if (error != 0)
return error;
@@ -207,16 +205,25 @@
tf->tf_rbp = regs[_REG_RBP];
tf->tf_rbx = regs[_REG_RBX];
tf->tf_rax = regs[_REG_RAX];
- tf->tf_gs = 0;
- tf->tf_fs = 0;
- tf->tf_es = GSEL(GUDATA_SEL, SEL_UPL);
- tf->tf_ds = GSEL(GUDATA_SEL, SEL_UPL);
+ if (pk32) {
+ tf->tf_gs = regs[_REG_GS] & 0xffff;
+ tf->tf_fs = regs[_REG_FS] & 0xffff;
+ tf->tf_es = regs[_REG_ES] & 0xffff;
+ tf->tf_ds = regs[_REG_DS] & 0xffff;
+ tf->tf_cs = regs[_REG_CS] & 0xffff;
+ tf->tf_ss = regs[_REG_SS] & 0xffff;
+ } else {
+ tf->tf_gs = 0;
+ tf->tf_fs = 0;
+ tf->tf_es = GSEL(GUDATA_SEL, SEL_UPL);
+ tf->tf_ds = GSEL(GUDATA_SEL, SEL_UPL);
+ tf->tf_cs = LSEL(LUCODE_SEL, SEL_UPL);
+ tf->tf_ss = LSEL(LUDATA_SEL, SEL_UPL);
+ }
/* trapno, err not touched */
tf->tf_rip = regs[_REG_RIP];
- tf->tf_cs = LSEL(LUCODE_SEL, SEL_UPL);
tf->tf_rflags = regs[_REG_RFLAGS];
tf->tf_rsp = regs[_REG_RSP];
- tf->tf_ss = LSEL(LUDATA_SEL, SEL_UPL);
#ifdef XENPV
/* see comment in cpu_setmcontext */
@@ -230,11 +237,6 @@
int
process_write_fpregs(struct lwp *l, const struct fpreg *regs, size_t sz)
{
- struct proc *p = l->l_proc;
-
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
process_write_fpregs_xmm(l, ®s->fxstate);
return 0;
@@ -243,13 +245,8 @@
int
process_write_dbregs(struct lwp *l, const struct dbreg *regs, size_t sz)
{
- struct proc *p = l->l_proc;
int error;
- if (p->p_flag & PK_32) {
- return EINVAL;
- }
-
/*
* Check for security violations.
*/
@@ -279,15 +276,12 @@
process_set_pc(struct lwp *l, void *addr)
{
struct trapframe *tf = process_frame(l);
- struct proc *p = l->l_proc;
+ const bool pk32 = (l->l_proc->p_flag & PK_32) != 0;
+ const uint64_t rip = (uint64_t)addr;
- if (p->p_flag & PK_32) {
+ if (rip >= (pk32 ? VM_MAXUSER_ADDRESS32 : VM_MAXUSER_ADDRESS))
return EINVAL;
- }
-
- if ((uint64_t)addr >= VM_MAXUSER_ADDRESS)
- return EINVAL;
- tf->tf_rip = (uint64_t)addr;
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