From 072de836f53be56a70cecf70b43ae43b7ce17376 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Mon, 11 Dec 2023 10:08:36 +0000
Subject: [PATCH] mk-rootfs.sh
---
kernel/arch/x86/mm/extable.c | 141 +++++++++++++++++++++++------------------------
1 files changed, 69 insertions(+), 72 deletions(-)
diff --git a/kernel/arch/x86/mm/extable.c b/kernel/arch/x86/mm/extable.c
index 79e9955..a7eae1c 100644
--- a/kernel/arch/x86/mm/extable.c
+++ b/kernel/arch/x86/mm/extable.c
@@ -1,14 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0-only
#include <linux/extable.h>
#include <linux/uaccess.h>
#include <linux/sched/debug.h>
#include <xen/xen.h>
#include <asm/fpu/internal.h>
+#include <asm/sev-es.h>
#include <asm/traps.h>
#include <asm/kdebug.h>
typedef bool (*ex_handler_t)(const struct exception_table_entry *,
- struct pt_regs *, int);
+ struct pt_regs *, int, unsigned long,
+ unsigned long);
static inline unsigned long
ex_fixup_addr(const struct exception_table_entry *x)
@@ -22,7 +25,9 @@
}
__visible bool ex_handler_default(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
regs->ip = ex_fixup_addr(fixup);
return true;
@@ -30,60 +35,15 @@
EXPORT_SYMBOL(ex_handler_default);
__visible bool ex_handler_fault(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
regs->ip = ex_fixup_addr(fixup);
regs->ax = trapnr;
return true;
}
EXPORT_SYMBOL_GPL(ex_handler_fault);
-
-/*
- * Handler for UD0 exception following a failed test against the
- * result of a refcount inc/dec/add/sub.
- */
-__visible bool ex_handler_refcount(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
-{
- /* First unconditionally saturate the refcount. */
- *(int *)regs->cx = INT_MIN / 2;
-
- /*
- * Strictly speaking, this reports the fixup destination, not
- * the fault location, and not the actually overflowing
- * instruction, which is the instruction before the "js", but
- * since that instruction could be a variety of lengths, just
- * report the location after the overflow, which should be close
- * enough for finding the overflow, as it's at least back in
- * the function, having returned from .text.unlikely.
- */
- regs->ip = ex_fixup_addr(fixup);
-
- /*
- * This function has been called because either a negative refcount
- * value was seen by any of the refcount functions, or a zero
- * refcount value was seen by refcount_dec().
- *
- * If we crossed from INT_MAX to INT_MIN, OF (Overflow Flag: result
- * wrapped around) will be set. Additionally, seeing the refcount
- * reach 0 will set ZF (Zero Flag: result was zero). In each of
- * these cases we want a report, since it's a boundary condition.
- * The SF case is not reported since it indicates post-boundary
- * manipulations below zero or above INT_MAX. And if none of the
- * flags are set, something has gone very wrong, so report it.
- */
- if (regs->flags & (X86_EFLAGS_OF | X86_EFLAGS_ZF)) {
- bool zero = regs->flags & X86_EFLAGS_ZF;
-
- refcount_error_report(regs, zero ? "hit zero" : "overflow");
- } else if ((regs->flags & X86_EFLAGS_SF) == 0) {
- /* Report if none of OF, ZF, nor SF are set. */
- refcount_error_report(regs, "unexpected saturation");
- }
-
- return true;
-}
-EXPORT_SYMBOL(ex_handler_refcount);
/*
* Handler for when we fail to restore a task's FPU state. We should never get
@@ -96,7 +56,9 @@
* out all the FPU registers) if we can't restore from the task's FPU state.
*/
__visible bool ex_handler_fprestore(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
regs->ip = ex_fixup_addr(fixup);
@@ -108,20 +70,35 @@
}
EXPORT_SYMBOL_GPL(ex_handler_fprestore);
-__visible bool ex_handler_ext(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+__visible bool ex_handler_uaccess(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
- /* Special hack for uaccess_err */
- current->thread.uaccess_err = 1;
+ WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
regs->ip = ex_fixup_addr(fixup);
return true;
}
-EXPORT_SYMBOL(ex_handler_ext);
+EXPORT_SYMBOL(ex_handler_uaccess);
+
+__visible bool ex_handler_copy(const struct exception_table_entry *fixup,
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
+{
+ WARN_ONCE(trapnr == X86_TRAP_GP, "General protection fault in user access. Non-canonical address?");
+ regs->ip = ex_fixup_addr(fixup);
+ regs->ax = trapnr;
+ return true;
+}
+EXPORT_SYMBOL(ex_handler_copy);
__visible bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
- if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pF)\n",
+ if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n",
(unsigned int)regs->cx, regs->ip, (void *)regs->ip))
show_stack_regs(regs);
@@ -134,9 +111,11 @@
EXPORT_SYMBOL(ex_handler_rdmsr_unsafe);
__visible bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
- if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pF)\n",
+ if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n",
(unsigned int)regs->cx, (unsigned int)regs->dx,
(unsigned int)regs->ax, regs->ip, (void *)regs->ip))
show_stack_regs(regs);
@@ -148,30 +127,37 @@
EXPORT_SYMBOL(ex_handler_wrmsr_unsafe);
__visible bool ex_handler_clear_fs(const struct exception_table_entry *fixup,
- struct pt_regs *regs, int trapnr)
+ struct pt_regs *regs, int trapnr,
+ unsigned long error_code,
+ unsigned long fault_addr)
{
if (static_cpu_has(X86_BUG_NULL_SEG))
asm volatile ("mov %0, %%fs" : : "rm" (__USER_DS));
asm volatile ("mov %0, %%fs" : : "rm" (0));
- return ex_handler_default(fixup, regs, trapnr);
+ return ex_handler_default(fixup, regs, trapnr, error_code, fault_addr);
}
EXPORT_SYMBOL(ex_handler_clear_fs);
-__visible bool ex_has_fault_handler(unsigned long ip)
+enum handler_type ex_get_fault_handler_type(unsigned long ip)
{
const struct exception_table_entry *e;
ex_handler_t handler;
e = search_exception_tables(ip);
if (!e)
- return false;
+ return EX_HANDLER_NONE;
handler = ex_fixup_handler(e);
-
- return handler == ex_handler_fault;
+ if (handler == ex_handler_fault)
+ return EX_HANDLER_FAULT;
+ else if (handler == ex_handler_uaccess || handler == ex_handler_copy)
+ return EX_HANDLER_UACCESS;
+ else
+ return EX_HANDLER_OTHER;
}
__nocfi
-int fixup_exception(struct pt_regs *regs, int trapnr)
+int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
+ unsigned long fault_addr)
{
const struct exception_table_entry *e;
ex_handler_t handler;
@@ -195,7 +181,7 @@
return 0;
handler = ex_fixup_handler(e);
- return handler(e, regs, trapnr);
+ return handler(e, regs, trapnr, error_code, fault_addr);
}
extern unsigned int early_recursion_flag;
@@ -231,13 +217,24 @@
* result in a hard-to-debug panic.
*
* Keep in mind that not all vectors actually get here. Early
- * fage faults, for example, are special.
+ * page faults, for example, are special.
*/
- if (fixup_exception(regs, trapnr))
+ if (fixup_exception(regs, trapnr, regs->orig_ax, 0))
return;
- if (fixup_bug(regs, trapnr))
- return;
+ if (trapnr == X86_TRAP_UD) {
+ if (report_bug(regs->ip, regs) == BUG_TRAP_TYPE_WARN) {
+ /* Skip the ud2. */
+ regs->ip += LEN_UD2;
+ return;
+ }
+
+ /*
+ * If this was a BUG and report_bug returns or if this
+ * was just a normal #UD, we want to continue onward and
+ * crash.
+ */
+ }
fail:
early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
--
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