From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Subject: [patch V3 09/32] x86/exceptions: Make IST index zero based
Date: Sun, 14 Apr 2019 17:59:45 +0200 [thread overview]
Message-ID: <20190414160144.331772825@linutronix.de> (raw)
In-Reply-To: 20190414155936.679808307@linutronix.de
The defines for the exception stack (IST) array in the TSS are using the
SDM convention IST1 - IST7. That causes all sorts of code to subtract 1 for
array indices related to IST. That's confusing at best and does not provide
any value.
Make the indices zero based and fixup the usage sites. The only code which
needs to adjust the 0 based index is the interrupt descriptor setup which
needs to add 1 now.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
Documentation/x86/kernel-stacks | 8 ++++----
arch/x86/entry/entry_64.S | 4 ++--
arch/x86/include/asm/page_64_types.h | 13 ++++++++-----
arch/x86/kernel/cpu/common.c | 4 ++--
arch/x86/kernel/dumpstack_64.c | 14 +++++++-------
arch/x86/kernel/idt.c | 15 +++++++++------
arch/x86/kernel/irq_64.c | 2 +-
arch/x86/mm/fault.c | 2 +-
8 files changed, 34 insertions(+), 28 deletions(-)
--- a/Documentation/x86/kernel-stacks
+++ b/Documentation/x86/kernel-stacks
@@ -59,7 +59,7 @@ If that assumption is ever broken then t
The currently assigned IST stacks are :-
-* DOUBLEFAULT_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
+* ESTACK_DF. EXCEPTION_STKSZ (PAGE_SIZE).
Used for interrupt 8 - Double Fault Exception (#DF).
@@ -68,7 +68,7 @@ The currently assigned IST stacks are :-
Using a separate stack allows the kernel to recover from it well enough
in many cases to still output an oops.
-* NMI_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
+* ESTACK_NMI. EXCEPTION_STKSZ (PAGE_SIZE).
Used for non-maskable interrupts (NMI).
@@ -76,7 +76,7 @@ The currently assigned IST stacks are :-
middle of switching stacks. Using IST for NMI events avoids making
assumptions about the previous state of the kernel stack.
-* DEBUG_STACK. DEBUG_STKSZ
+* ESTACK_DB. DEBUG_STKSZ
Used for hardware debug interrupts (interrupt 1) and for software
debug interrupts (INT3).
@@ -86,7 +86,7 @@ The currently assigned IST stacks are :-
avoids making assumptions about the previous state of the kernel
stack.
-* MCE_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
+* ESTACK_MCE. EXCEPTION_STKSZ (PAGE_SIZE).
Used for interrupt 18 - Machine Check Exception (#MC).
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -841,7 +841,7 @@ apicinterrupt IRQ_WORK_VECTOR irq_work
/*
* Exception entry points.
*/
-#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + ((x) - 1) * 8)
+#define CPU_TSS_IST(x) PER_CPU_VAR(cpu_tss_rw) + (TSS_ist + (x) * 8)
/**
* idtentry - Generate an IDT entry stub
@@ -1129,7 +1129,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \
hv_stimer0_callback_vector hv_stimer0_vector_handler
#endif /* CONFIG_HYPERV */
-idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK
+idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=ESTACK_DB
idtentry int3 do_int3 has_error_code=0
idtentry stack_segment do_stack_segment has_error_code=1
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -24,11 +24,14 @@
#define IRQ_STACK_ORDER (2 + KASAN_STACK_ORDER)
#define IRQ_STACK_SIZE (PAGE_SIZE << IRQ_STACK_ORDER)
-#define DOUBLEFAULT_STACK 1
-#define NMI_STACK 2
-#define DEBUG_STACK 3
-#define MCE_STACK 4
-#define N_EXCEPTION_STACKS 4 /* hw limit: 7 */
+/*
+ * The index for the tss.ist[] array. The hardware limit is 7 entries.
+ */
+#define ESTACK_DF 0
+#define ESTACK_NMI 1
+#define ESTACK_DB 2
+#define ESTACK_MCE 3
+#define N_EXCEPTION_STACKS 4
/*
* Set __PAGE_OFFSET to the most negative possible address +
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -516,7 +516,7 @@ DEFINE_PER_CPU(struct cpu_entry_area *,
*/
static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
[0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
- [DEBUG_STACK - 1] = DEBUG_STKSZ
+ [ESTACK_DB] = DEBUG_STKSZ
};
#endif
@@ -1760,7 +1760,7 @@ void cpu_init(void)
estacks += exception_stack_sizes[v];
oist->ist[v] = t->x86_tss.ist[v] =
(unsigned long)estacks;
- if (v == DEBUG_STACK-1)
+ if (v == ESTACK_DB)
per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
}
}
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -18,16 +18,16 @@
#include <asm/stacktrace.h>
-static char *exception_stack_names[N_EXCEPTION_STACKS] = {
- [ DOUBLEFAULT_STACK-1 ] = "#DF",
- [ NMI_STACK-1 ] = "NMI",
- [ DEBUG_STACK-1 ] = "#DB",
- [ MCE_STACK-1 ] = "#MC",
+static const char *exception_stack_names[N_EXCEPTION_STACKS] = {
+ [ ESTACK_DF ] = "#DF",
+ [ ESTACK_NMI ] = "NMI",
+ [ ESTACK_DB ] = "#DB",
+ [ ESTACK_MCE ] = "#MC",
};
-static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
+static const unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
[0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
- [DEBUG_STACK - 1] = DEBUG_STKSZ
+ [ESTACK_DB] = DEBUG_STKSZ
};
const char *stack_type_name(enum stack_type type)
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -41,9 +41,12 @@ struct idt_data {
#define SYSG(_vector, _addr) \
G(_vector, _addr, DEFAULT_STACK, GATE_INTERRUPT, DPL3, __KERNEL_CS)
-/* Interrupt gate with interrupt stack */
+/*
+ * Interrupt gate with interrupt stack. The _ist index is the index in
+ * the tss.ist[] array, but for the descriptor it needs to start at 1.
+ */
#define ISTG(_vector, _addr, _ist) \
- G(_vector, _addr, _ist, GATE_INTERRUPT, DPL0, __KERNEL_CS)
+ G(_vector, _addr, _ist + 1, GATE_INTERRUPT, DPL0, __KERNEL_CS)
/* Task gate */
#define TSKG(_vector, _gdt) \
@@ -180,11 +183,11 @@ gate_desc debug_idt_table[IDT_ENTRIES] _
* cpu_init() when the TSS has been initialized.
*/
static const __initconst struct idt_data ist_idts[] = {
- ISTG(X86_TRAP_DB, debug, DEBUG_STACK),
- ISTG(X86_TRAP_NMI, nmi, NMI_STACK),
- ISTG(X86_TRAP_DF, double_fault, DOUBLEFAULT_STACK),
+ ISTG(X86_TRAP_DB, debug, ESTACK_DB),
+ ISTG(X86_TRAP_NMI, nmi, ESTACK_NMI),
+ ISTG(X86_TRAP_DF, double_fault, ESTACK_DF),
#ifdef CONFIG_X86_MCE
- ISTG(X86_TRAP_MC, &machine_check, MCE_STACK),
+ ISTG(X86_TRAP_MC, &machine_check, ESTACK_MCE),
#endif
};
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -61,7 +61,7 @@ static inline void stack_overflow_check(
return;
oist = this_cpu_ptr(&orig_ist);
- estack_top = (u64)oist->ist[DEBUG_STACK];
+ estack_top = (u64)oist->ist[ESTACK_DB];
estack_bottom = estack_top - DEBUG_STKSZ + STACK_MARGIN;
if (regs->sp >= estack_bottom && regs->sp <= estack_top)
return;
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -793,7 +793,7 @@ no_context(struct pt_regs *regs, unsigne
if (is_vmalloc_addr((void *)address) &&
(((unsigned long)tsk->stack - 1 - address < PAGE_SIZE) ||
address - ((unsigned long)tsk->stack + THREAD_SIZE) < PAGE_SIZE)) {
- unsigned long stack = this_cpu_read(orig_ist.ist[DOUBLEFAULT_STACK]) - sizeof(void *);
+ unsigned long stack = this_cpu_read(orig_ist.ist[ESTACK_DF]) - sizeof(void *);
/*
* We're likely to be running with very little stack space
* left. It's plausible that we'd hit this condition but
next prev parent reply other threads:[~2019-04-14 16:04 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-14 15:59 [patch V3 00/32] x86: Add guard pages to exception and interrupt stacks Thomas Gleixner
2019-04-14 15:59 ` [patch V3 01/32] mm/slab: Fix broken stack trace storage Thomas Gleixner
2019-04-14 16:16 ` Andy Lutomirski
2019-04-14 16:34 ` Thomas Gleixner
2019-04-15 9:02 ` [patch V4 " Thomas Gleixner
2019-04-15 13:23 ` Josh Poimboeuf
2019-04-15 16:07 ` Thomas Gleixner
2019-04-15 16:16 ` Josh Poimboeuf
2019-04-15 17:05 ` Andy Lutomirski
2019-04-15 21:22 ` Thomas Gleixner
2019-04-16 11:37 ` Vlastimil Babka
2019-04-16 14:10 ` [patch V5 01/32] mm/slab: Remove " Thomas Gleixner
2019-04-16 15:16 ` Vlastimil Babka
2019-04-15 21:20 ` [patch V4 01/32] mm/slab: Fix " Thomas Gleixner
2019-04-15 16:21 ` Peter Zijlstra
2019-04-15 16:58 ` [patch V3 " Andy Lutomirski
2019-04-14 15:59 ` [patch V3 02/32] x86/irq/64: Limit IST stack overflow check to #DB stack Thomas Gleixner
2019-04-17 14:02 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 03/32] x86/dumpstack: Fix off-by-one errors in stack identification Thomas Gleixner
2019-04-17 14:03 ` [tip:x86/irq] " tip-bot for Andy Lutomirski
2019-04-14 15:59 ` [patch V3 04/32] x86/irq/64: Remove a hardcoded irq_stack_union access Thomas Gleixner
2019-04-17 14:03 ` [tip:x86/irq] " tip-bot for Andy Lutomirski
2019-04-14 15:59 ` [patch V3 05/32] x86/irq/64: Sanitize the top/bottom confusion Thomas Gleixner
2019-04-17 14:04 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 06/32] x86/idt: Remove unused macro SISTG Thomas Gleixner
2019-04-17 14:05 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 07/32] x86/64: Remove stale CURRENT_MASK Thomas Gleixner
2019-04-17 14:06 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 08/32] x86/exceptions: Remove unused stack defines on 32bit Thomas Gleixner
2019-04-17 14:06 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` Thomas Gleixner [this message]
2019-04-17 14:07 ` [tip:x86/irq] x86/exceptions: Make IST index zero based tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 10/32] x86/cpu_entry_area: Cleanup setup functions Thomas Gleixner
2019-04-17 14:08 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 11/32] x86/exceptions: Add structs for exception stacks Thomas Gleixner
2019-04-16 18:20 ` Sean Christopherson
2019-04-17 14:08 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 12/32] x86/cpu_entry_area: Prepare for IST guard pages Thomas Gleixner
2019-04-17 14:09 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 13/32] x86/cpu_entry_area: Provide exception stack accessor Thomas Gleixner
2019-04-17 14:10 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 14/32] x86/traps: Use cpu_entry_area instead of orig_ist Thomas Gleixner
2019-04-17 14:10 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 15/32] x86/irq/64: Use cpu entry area " Thomas Gleixner
2019-04-17 14:11 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 16/32] x86/dumpstack/64: Use cpu_entry_area " Thomas Gleixner
2019-04-17 14:12 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 17/32] x86/cpu: Prepare TSS.IST setup for guard pages Thomas Gleixner
2019-04-17 14:13 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 18/32] x86/cpu: Remove orig_ist array Thomas Gleixner
2019-04-17 14:13 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 19/32] x86/exceptions: Disconnect IST index and stack order Thomas Gleixner
2019-04-17 14:14 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 20/32] x86/exceptions: Enable IST guard pages Thomas Gleixner
2019-04-17 14:15 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 21/32] x86/exceptions: Split debug IST stack Thomas Gleixner
2019-04-16 22:07 ` Sean Christopherson
2019-04-17 14:15 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 22/32] x86/dumpstack/64: Speedup in_exception_stack() Thomas Gleixner
2019-04-17 14:16 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 15:59 ` [patch V3 23/32] x86/irq/32: Define IRQ_STACK_SIZE Thomas Gleixner
2019-04-17 14:17 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 24/32] x86/irq/32: Make irq stack a character array Thomas Gleixner
2019-04-17 14:18 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 25/32] x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr Thomas Gleixner
2019-04-17 14:18 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 26/32] x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr Thomas Gleixner
2019-04-17 14:19 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 27/32] x86/irq/32: Invoke irq_ctx_init() from init_IRQ() Thomas Gleixner
2019-04-17 14:20 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 28/32] x86/irq/32: Handle irq stack allocation failure proper Thomas Gleixner
2019-04-17 14:20 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 29/32] x86/irq/64: Init hardirq_stack_ptr during CPU hotplug Thomas Gleixner
2019-04-17 14:21 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
2019-04-14 16:00 ` [patch V3 30/32] x86/irq/64: Split the IRQ stack into its own pages Thomas Gleixner
2019-04-17 14:22 ` [tip:x86/irq] " tip-bot for Andy Lutomirski
2019-04-14 16:00 ` [patch V3 31/32] x86/irq/64: Remap the IRQ stack with guard pages Thomas Gleixner
2019-04-17 14:22 ` [tip:x86/irq] " tip-bot for Andy Lutomirski
2019-04-14 16:00 ` [patch V3 32/32] x86/irq/64: Remove stack overflow debug code Thomas Gleixner
2019-04-17 14:23 ` [tip:x86/irq] " tip-bot for Thomas Gleixner
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