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authorThomas Gleixner <tglx@linutronix.de>2020-06-10 08:37:01 +0200
committerThomas Gleixner <tglx@linutronix.de>2020-06-11 15:15:29 +0200
commitf0178fc01fe46bab6a95415f5647d1a74efcad1b (patch)
treebf263d8cacf2ada33dea4cbc16ee5fd46b0109d4 /arch
parent2823e83a3dc0f54d23db67ca07d74b9c8bb1fdda (diff)
x86/entry: Unbreak __irqentry_text_start/end magic
The entry rework moved interrupt entry code from the irqentry to the noinstr section which made the irqentry section empty. This breaks boundary checks which rely on the __irqentry_text_start/end markers to find out whether a function in a stack trace is interrupt/exception entry code. This affects the function graph tracer and filter_irq_stacks(). As the IDT entry points are all sequentialy emitted this is rather simple to unbreak by injecting __irqentry_text_start/end as global labels. To make this work correctly: - Remove the IRQENTRY_TEXT section from the x86 linker script - Define __irqentry so it breaks the build if it's used - Adjust the entry mirroring in PTI - Remove the redundant kprobes and unwinder bound checks Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/entry/entry_32.S11
-rw-r--r--arch/x86/entry/entry_64.S11
-rw-r--r--arch/x86/include/asm/irq.h7
-rw-r--r--arch/x86/kernel/kprobes/core.c7
-rw-r--r--arch/x86/kernel/kprobes/opt.c4
-rw-r--r--arch/x86/kernel/unwind_frame.c8
-rw-r--r--arch/x86/kernel/vmlinux.lds.S1
-rw-r--r--arch/x86/mm/pti.c4
8 files changed, 31 insertions, 22 deletions
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 2d29f77a3601..024d7d276cd4 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -743,10 +743,19 @@ SYM_CODE_END(asm_\cfunc)
/*
* Include the defines which emit the idt entries which are shared
- * shared between 32 and 64 bit.
+ * shared between 32 and 64 bit and emit the __irqentry_text_* markers
+ * so the stacktrace boundary checks work.
*/
+ .align 16
+ .globl __irqentry_text_start
+__irqentry_text_start:
+
#include <asm/idtentry.h>
+ .align 16
+ .globl __irqentry_text_end
+__irqentry_text_end:
+
/*
* %eax: prev task
* %edx: next task
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 8ecaeee53653..d2a00c97e53f 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -478,10 +478,19 @@ SYM_CODE_END(\asmsym)
/*
* Include the defines which emit the idt entries which are shared
- * shared between 32 and 64 bit.
+ * shared between 32 and 64 bit and emit the __irqentry_text_* markers
+ * so the stacktrace boundary checks work.
*/
+ .align 16
+ .globl __irqentry_text_start
+__irqentry_text_start:
+
#include <asm/idtentry.h>
+ .align 16
+ .globl __irqentry_text_end
+__irqentry_text_end:
+
SYM_CODE_START_LOCAL(common_interrupt_return)
SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL)
#ifdef CONFIG_DEBUG_ENTRY
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index f73dd3f8b043..528c8a71fe7f 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -11,6 +11,13 @@
#include <asm/apicdef.h>
#include <asm/irq_vectors.h>
+/*
+ * The irq entry code is in the noinstr section and the start/end of
+ * __irqentry_text is emitted via labels. Make the build fail if
+ * something moves a C function into the __irq_entry section.
+ */
+#define __irq_entry __invalid_section
+
static inline int irq_canonicalize(int irq)
{
return ((irq == 2) ? 9 : irq);
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 85de8fa69b24..3bafe1bd4dc7 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1073,13 +1073,6 @@ NOKPROBE_SYMBOL(kprobe_fault_handler);
int __init arch_populate_kprobe_blacklist(void)
{
- int ret;
-
- ret = kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
- (unsigned long)__irqentry_text_end);
- if (ret)
- return ret;
-
return kprobe_add_area_blacklist((unsigned long)__entry_text_start,
(unsigned long)__entry_text_end);
}
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 234f58e0fe8c..321c19950285 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -286,9 +286,7 @@ static int can_optimize(unsigned long paddr)
* stack handling and registers setup.
*/
if (((paddr >= (unsigned long)__entry_text_start) &&
- (paddr < (unsigned long)__entry_text_end)) ||
- ((paddr >= (unsigned long)__irqentry_text_start) &&
- (paddr < (unsigned long)__irqentry_text_end)))
+ (paddr < (unsigned long)__entry_text_end)))
return 0;
/* Check there is enough space for a relative jump. */
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index 54226110bc7f..722a85f3b2dd 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -74,13 +74,7 @@ static bool in_entry_code(unsigned long ip)
{
char *addr = (char *)ip;
- if (addr >= __entry_text_start && addr < __entry_text_end)
- return true;
-
- if (addr >= __irqentry_text_start && addr < __irqentry_text_end)
- return true;
-
- return false;
+ return addr >= __entry_text_start && addr < __entry_text_end;
}
static inline unsigned long *last_frame(struct unwind_state *state)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 1bf7e312361f..b4c6b6f35548 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -134,7 +134,6 @@ SECTIONS
KPROBES_TEXT
ALIGN_ENTRY_TEXT_BEGIN
ENTRY_TEXT
- IRQENTRY_TEXT
ALIGN_ENTRY_TEXT_END
SOFTIRQENTRY_TEXT
*(.fixup)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index a3c6757a65c7..a8a924b3c335 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -492,12 +492,12 @@ static void __init pti_setup_espfix64(void)
}
/*
- * Clone the populated PMDs of the entry and irqentry text and force it RO.
+ * Clone the populated PMDs of the entry text and force it RO.
*/
static void pti_clone_entry_text(void)
{
pti_clone_pgtable((unsigned long) __entry_text_start,
- (unsigned long) __irqentry_text_end,
+ (unsigned long) __entry_text_end,
PTI_CLONE_PMD);
}