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x86/cpu: Prepare TSS.IST setup for guard pages

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Convert the TSS.IST setup code to use the cpu entry area information
directly instead of assuming a linear mapping of the IST stacks.

The store to orig_ist[] is no longer required as there are no users
anymore.

This is the last preparatory step towards IST guard pages.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Chang S. Bae" <chang.seok.bae@intel.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160145.061686012@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-04-14 17:59:53 +02:00 committed by Borislav Petkov
parent afcd21dad8
commit f6ef73224a
1 changed files with 7 additions and 28 deletions
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35
arch/x86/kernel/cpu/common.c
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@ -507,19 +507,6 @@ void load_percpu_segment(int cpu)
DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area);
#endif
#ifdef CONFIG_X86_64
/*
* Special IST stacks which the CPU switches to when it calls
* an IST-marked descriptor entry. Up to 7 stacks (hardware
* limit), all of them are 4K, except the debug stack which
* is 8K.
*/
static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
[0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
[ESTACK_DB] = DEBUG_STKSZ
};
#endif
/* Load the original GDT from the per-cpu structure */
void load_direct_gdt(int cpu)
{
@ -1690,17 +1677,14 @@ static void setup_getcpu(int cpu)
* initialized (naturally) in the bootstrap process, such as the GDT
* and IDT. We reload them nevertheless, this function acts as a
* 'CPU state barrier', nothing should get across.
* A lot of state is already set up in PDA init for 64 bit
*/
#ifdef CONFIG_X86_64
void cpu_init(void)
{
struct orig_ist *oist;
int cpu = raw_smp_processor_id();
struct task_struct *me;
struct tss_struct *t;
unsigned long v;
int cpu = raw_smp_processor_id();
int i;
wait_for_master_cpu(cpu);
@ -1715,7 +1699,6 @@ void cpu_init(void)
load_ucode_ap();
t = &per_cpu(cpu_tss_rw, cpu);
oist = &per_cpu(orig_ist, cpu);
#ifdef CONFIG_NUMA
if (this_cpu_read(numa_node) == 0 &&
@ -1753,16 +1736,12 @@ void cpu_init(void)
/*
* set up and load the per-CPU TSS
*/
if (!oist->ist[0]) {
char *estacks = (char *)&get_cpu_entry_area(cpu)->estacks;
for (v = 0; v < N_EXCEPTION_STACKS; v++) {
estacks += exception_stack_sizes[v];
oist->ist[v] = t->x86_tss.ist[v] =
(unsigned long)estacks;
if (v == ESTACK_DB)
per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
}
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.io_bitmap_base = IO_BITMAP_OFFSET;