* [PATCH 1/2] x86/idt: split out idt routines
2019-05-07 8:52 [PATCH 0/2] x86/boot: support to handle exception in early boot Pingfan Liu
@ 2019-05-07 8:52 ` Pingfan Liu
2019-05-07 8:52 ` [PATCH 2/2] x86/boot: set up idt for very early boot stage Pingfan Liu
1 sibling, 0 replies; 3+ messages in thread
From: Pingfan Liu @ 2019-05-07 8:52 UTC (permalink / raw)
To: x86
Cc: Pingfan Liu, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
H. Peter Anvin, Kirill A. Shutemov, Cao jin, Wei Huang, Chao Fan,
Nicolai Stange, Dou Liyang, linux-kernel
Some idt routines can be reused in early boot stage. Splitting them out.
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: Wei Huang <wei@redhat.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
---
arch/x86/include/asm/idt.h | 64 ++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/idt.c | 58 +----------------------------------------
2 files changed, 65 insertions(+), 57 deletions(-)
create mode 100644 arch/x86/include/asm/idt.h
diff --git a/arch/x86/include/asm/idt.h b/arch/x86/include/asm/idt.h
new file mode 100644
index 0000000..147f128
--- /dev/null
+++ b/arch/x86/include/asm/idt.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_IDT_H
+#define _ASM_X86_IDT_H
+
+#include <asm/desc_defs.h>
+
+struct idt_data {
+ unsigned int vector;
+ unsigned int segment;
+ struct idt_bits bits;
+ const void *addr;
+};
+
+#define DPL0 0x0
+#define DPL3 0x3
+
+#define DEFAULT_STACK 0
+
+#define G(_vector, _addr, _ist, _type, _dpl, _segment) \
+ { \
+ .vector = _vector, \
+ .bits.ist = _ist, \
+ .bits.type = _type, \
+ .bits.dpl = _dpl, \
+ .bits.p = 1, \
+ .addr = _addr, \
+ .segment = _segment, \
+ }
+
+/* Interrupt gate */
+#define INTG(_vector, _addr) \
+ G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
+
+/* System interrupt gate */
+#define SYSG(_vector, _addr) \
+ G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
+
+/* Interrupt gate with interrupt stack */
+#define ISTG(_vector, _addr, _ist) \
+ G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS)
+
+/* System interrupt gate with interrupt stack */
+#define SISTG(_vector, _addr, _ist) \
+ G(_vector, _addr, _ist, GATE_INTERRUPT, DPL3, __KERNEL_CS)
+
+/* Task gate */
+#define TSKG(_vector, _gdt) \
+ G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
+
+static inline void idt_init_desc(gate_desc *gate, const struct idt_data *d)
+{
+ unsigned long addr = (unsigned long) d->addr;
+
+ gate->offset_low = (u16) addr;
+ gate->segment = (u16) d->segment;
+ gate->bits = d->bits;
+ gate->offset_middle = (u16) (addr >> 16);
+#ifdef CONFIG_X86_64
+ gate->offset_high = (u32) (addr >> 32);
+ gate->reserved = 0;
+#endif
+}
+
+#endif
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 01adea2..80b811a 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -9,49 +9,7 @@
#include <asm/proto.h>
#include <asm/desc.h>
#include <asm/hw_irq.h>
-
-struct idt_data {
- unsigned int vector;
- unsigned int segment;
- struct idt_bits bits;
- const void *addr;
-};
-
-#define DPL0 0x0
-#define DPL3 0x3
-
-#define DEFAULT_STACK 0
-
-#define G(_vector, _addr, _ist, _type, _dpl, _segment) \
- { \
- .vector = _vector, \
- .bits.ist = _ist, \
- .bits.type = _type, \
- .bits.dpl = _dpl, \
- .bits.p = 1, \
- .addr = _addr, \
- .segment = _segment, \
- }
-
-/* Interrupt gate */
-#define INTG(_vector, _addr) \
- G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL0, __KERNEL_CS)
-
-/* System interrupt gate */
-#define SYSG(_vector, _addr) \
- G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
-
-/* Interrupt gate with interrupt stack */
-#define ISTG(_vector, _addr, _ist) \
- G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS)
-
-/* System interrupt gate with interrupt stack */
-#define SISTG(_vector, _addr, _ist) \
- G(_vector, _addr, _ist, GATE_INTERRUPT, DPL3, __KERNEL_CS)
-
-/* Task gate */
-#define TSKG(_vector, _gdt) \
- G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
+#include <asm/idt.h>
/*
* Early traps running on the DEFAULT_STACK because the other interrupt
@@ -202,20 +160,6 @@ const struct desc_ptr debug_idt_descr = {
};
#endif
-static inline void idt_init_desc(gate_desc *gate, const struct idt_data *d)
-{
- unsigned long addr = (unsigned long) d->addr;
-
- gate->offset_low = (u16) addr;
- gate->segment = (u16) d->segment;
- gate->bits = d->bits;
- gate->offset_middle = (u16) (addr >> 16);
-#ifdef CONFIG_X86_64
- gate->offset_high = (u32) (addr >> 32);
- gate->reserved = 0;
-#endif
-}
-
static void
idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sys)
{
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] x86/boot: set up idt for very early boot stage
2019-05-07 8:52 [PATCH 0/2] x86/boot: support to handle exception in early boot Pingfan Liu
2019-05-07 8:52 ` [PATCH 1/2] x86/idt: split out idt routines Pingfan Liu
@ 2019-05-07 8:52 ` Pingfan Liu
1 sibling, 0 replies; 3+ messages in thread
From: Pingfan Liu @ 2019-05-07 8:52 UTC (permalink / raw)
To: x86
Cc: Pingfan Liu, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
H. Peter Anvin, Kirill A. Shutemov, Cao jin, Wei Huang, Chao Fan,
Nicolai Stange, Dou Liyang, linux-kernel
The boot code becomes a little complicated, and hits some bugs, e.g.
Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in
boot_params") broke kexec boot on EFI systems.
There is few hint when bug happens. Catching the exception and printing
message can give a immediate help, instead of adding more debug_putstr() to
narraw down the problem.
At present, page fault exception handler is added. And the printed out
message looks like:
early boot page fault:
ENTRY(startup_64) is at: 000000047f67d200
nip: 000000047fdeedd3
fault address: fffffffeef6fde30
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: Wei Huang <wei@redhat.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
---
arch/x86/boot/compressed/head_64.S | 11 +++++++
arch/x86/boot/compressed/misc.c | 61 ++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+)
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index e4a25f9..f589aa2 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -527,6 +527,10 @@ relocated:
shrq $3, %rcx
rep stosq
+ pushq %rsi /* Save the real mode argument */
+ leaq startup_64(%rip), %rdi
+ call setup_early_boot_idt
+ popq %rsi
/*
* Do the extraction, and jump to the new kernel..
*/
@@ -659,6 +663,13 @@ no_longmode:
#include "../../kernel/verify_cpu.S"
+ .code64
+.align 8
+ENTRY(boot_page_fault)
+ mov 8(%rsp), %rdi
+ call do_boot_page_fault
+ iretq
+
.data
gdt64:
.word gdt_end - gdt
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 475a3c6..8aaa582 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -76,6 +76,11 @@ static int lines, cols;
#ifdef CONFIG_KERNEL_LZ4
#include "../../../../lib/decompress_unlz4.c"
#endif
+
+#include "../../include/asm/desc.h"
+#include "../../include/asm/idt.h"
+#include "../../include/asm/traps.h"
+
/*
* NOTE: When adding a new decompressor, please update the analysis in
* ../header.S.
@@ -429,3 +434,59 @@ void fortify_panic(const char *name)
{
error("detected buffer overflow");
}
+
+static unsigned long rt_startup_64;
+
+void do_boot_page_fault(unsigned long retaddr)
+{
+ struct desc_ptr idt = { .address = 0, .size = 0 };
+ unsigned long fault_address = read_cr2();
+
+ debug_putstr("early boot page fault:\n");
+ debug_putstr("ENTRY(startup_64) is at: ");
+ debug_puthex(rt_startup_64);
+ debug_putstr("\n");
+ debug_putstr("nip: ");
+ debug_puthex(retaddr);
+ debug_putstr("\n");
+ debug_putstr("fault address: ");
+ debug_puthex(fault_address);
+ debug_putstr("\n");
+
+ load_idt(&idt);
+}
+
+asmlinkage void boot_page_fault(void);
+
+static struct idt_data boot_idts[] = {
+ INTG(X86_TRAP_PF, 0),
+};
+
+static gate_desc early_boot_idt_table[IDT_ENTRIES] __page_aligned_bss;
+
+static struct desc_ptr early_boot_idt_descr __ro_after_init = {
+ .size = (IDT_ENTRIES * 2 * sizeof(unsigned long)) - 1,
+};
+
+static void
+idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size)
+{
+ gate_desc desc;
+
+ for (; size > 0; t++, size--) {
+ idt_init_desc(&desc, t);
+ write_idt_entry(idt, t->vector, &desc);
+ }
+}
+
+void setup_early_boot_idt(unsigned long rip)
+{
+ rt_startup_64 = rip;
+ /* fill it with runtime address */
+ boot_idts[0].addr = boot_page_fault;
+ early_boot_idt_descr.address = (unsigned long)early_boot_idt_table;
+
+ idt_setup_from_table(early_boot_idt_table, boot_idts,
+ ARRAY_SIZE(boot_idts));
+ load_idt(&early_boot_idt_descr);
+}
--
2.7.4
^ permalink raw reply related [flat|nested] 3+ messages in thread