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x86/exceptions: Disconnect IST index and stack order

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The entry order of the TSS.IST array and the order of the stack
storage/mapping are not required to be the same.

With the upcoming split of the debug stack this is going to fall apart as
the number of TSS.IST array entries stays the same while the actual stacks
are increasing.

Make them separate so that code like dumpstack can just utilize the mapping
order. The IST index is solely required for the actual TSS.IST array
initialization.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160145.241588113@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-04-14 17:59:55 +02:00 committed by Borislav Petkov
parent 4d68c3d0ec
commit 3207426925
6 changed files with 27 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/entry/entry_64.S
View File

@ -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=ESTACK_DB
idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=IST_INDEX_DB
idtentry int3 do_int3 has_error_code=0
idtentry stack_segment do_stack_segment has_error_code=1

11
arch/x86/include/asm/cpu_entry_area.h
View File

@ -35,6 +35,17 @@ struct cea_exception_stacks {
ESTACKS_MEMBERS(0)
};
/*
* The exception stack ordering in [cea_]exception_stacks
*/
enum exception_stack_ordering {
ESTACK_DF,
ESTACK_NMI,
ESTACK_DB,
ESTACK_MCE,
N_EXCEPTION_STACKS
};
#define CEA_ESTACK_SIZE(st) \
sizeof(((struct cea_exception_stacks *)0)->st## _stack)

9
arch/x86/include/asm/page_64_types.h
View File

@ -27,11 +27,10 @@
/*
* 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
#define IST_INDEX_DF 0
#define IST_INDEX_NMI 1
#define IST_INDEX_DB 2
#define IST_INDEX_MCE 3
/*
* Set __PAGE_OFFSET to the most negative possible address +

2
arch/x86/include/asm/stacktrace.h
View File

@ -9,6 +9,8 @@
#include <linux/uaccess.h>
#include <linux/ptrace.h>
#include <asm/cpu_entry_area.h>
#include <asm/switch_to.h>
enum stack_type {

10
arch/x86/kernel/cpu/common.c
View File

@ -1731,11 +1731,11 @@ void cpu_init(void)
* set up and load the per-CPU TSS
*/
if (!t->x86_tss.ist[0]) {
t->x86_tss.ist[ESTACK_DF] = __this_cpu_ist_top_va(DF);
t->x86_tss.ist[ESTACK_NMI] = __this_cpu_ist_top_va(NMI);
t->x86_tss.ist[ESTACK_DB] = __this_cpu_ist_top_va(DB);
t->x86_tss.ist[ESTACK_MCE] = __this_cpu_ist_top_va(MCE);
per_cpu(debug_stack_addr, cpu) = t->x86_tss.ist[ESTACK_DB];
t->x86_tss.ist[IST_INDEX_DF] = __this_cpu_ist_top_va(DF);
t->x86_tss.ist[IST_INDEX_NMI] = __this_cpu_ist_top_va(NMI);
t->x86_tss.ist[IST_INDEX_DB] = __this_cpu_ist_top_va(DB);
t->x86_tss.ist[IST_INDEX_MCE] = __this_cpu_ist_top_va(MCE);
per_cpu(debug_stack_addr, cpu) = t->x86_tss.ist[IST_INDEX_DB];
}
t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;

8
arch/x86/kernel/idt.c
View File

@ -183,11 +183,11 @@ gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
* cpu_init() when the TSS has been initialized.
*/
static const __initconst struct idt_data ist_idts[] = {
ISTG(X86_TRAP_DB, debug, ESTACK_DB),
ISTG(X86_TRAP_NMI, nmi, ESTACK_NMI),
ISTG(X86_TRAP_DF, double_fault, ESTACK_DF),
ISTG(X86_TRAP_DB, debug, IST_INDEX_DB),
ISTG(X86_TRAP_NMI, nmi, IST_INDEX_NMI),
ISTG(X86_TRAP_DF, double_fault, IST_INDEX_DF),
#ifdef CONFIG_X86_MCE
ISTG(X86_TRAP_MC, &machine_check, ESTACK_MCE),
ISTG(X86_TRAP_MC, &machine_check, IST_INDEX_MCE),
#endif
};