summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 15:56:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 15:56:41 -0700
commit8f147727030bf9e81331ab9b8f42d4611bb6a3d9 (patch)
treed3f1e2410174bb8c479590a8f1c7e204e3a48eaf /Documentation
parent53f8b081c184328b82c8a7b5e70b8243b3cea8bd (diff)
parent2c4645439e8f2f6e7c37f158feae6f6a82baa910 (diff)
Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 irq updates from Ingo Molnar: "Here are the main changes in this tree: - Introduce x86-64 IRQ/exception/debug stack guard pages to detect stack overflows immediately and deterministically. - Clean up over a decade worth of cruft accumulated. The outcome of this should be more clear-cut faults/crashes when any of the low level x86 CPU stacks overflow, instead of silent memory corruption and sporadic failures much later on" * 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) x86/irq: Fix outdated comments x86/irq/64: Remove stack overflow debug code x86/irq/64: Remap the IRQ stack with guard pages x86/irq/64: Split the IRQ stack into its own pages x86/irq/64: Init hardirq_stack_ptr during CPU hotplug x86/irq/32: Handle irq stack allocation failure proper x86/irq/32: Invoke irq_ctx_init() from init_IRQ() x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr x86/irq/32: Make irq stack a character array x86/irq/32: Define IRQ_STACK_SIZE x86/dumpstack/64: Speedup in_exception_stack() x86/exceptions: Split debug IST stack x86/exceptions: Enable IST guard pages x86/exceptions: Disconnect IST index and stack order x86/cpu: Remove orig_ist array x86/cpu: Prepare TSS.IST setup for guard pages x86/dumpstack/64: Use cpu_entry_area instead of orig_ist x86/irq/64: Use cpu entry area instead of orig_ist x86/traps: Use cpu_entry_area instead of orig_ist ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/x86/kernel-stacks13
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/x86/kernel-stacks b/Documentation/x86/kernel-stacks
index 9a0aa4d3a866..d1bfb0b95ee0 100644
--- a/Documentation/x86/kernel-stacks
+++ b/Documentation/x86/kernel-stacks
@@ -59,7 +59,7 @@ If that assumption is ever broken then the stacks will become corrupt.
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. EXCEPTION_STKSZ (PAGE_SIZE).
Used for hardware debug interrupts (interrupt 1) and for software
debug interrupts (INT3).
@@ -86,7 +86,12 @@ The currently assigned IST stacks are :-
avoids making assumptions about the previous state of the kernel
stack.
-* MCE_STACK. EXCEPTION_STKSZ (PAGE_SIZE).
+ To handle nested #DB correctly there exist two instances of DB stacks. On
+ #DB entry the IST stackpointer for #DB is switched to the second instance
+ so a nested #DB starts from a clean stack. The nested #DB switches
+ the IST stackpointer to a guard hole to catch triple nesting.
+
+* ESTACK_MCE. EXCEPTION_STKSZ (PAGE_SIZE).
Used for interrupt 18 - Machine Check Exception (#MC).