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[kernel] Use IST for kernel stacks for NMI, #DF, #PF

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We started actually running up against the page boundary for kernel
stacks and thus double-faulting on page faults from kernel space. So I
finally added IST stacks. Note that we currently just
increment/decrement the IST entry by a page when we enter the handler to
avoid clobbering on re-entry, but this means:

* these handlers need to be able to operate with only a page of stack
* kernel stacks always have to be >1 pages
* the amount of nesting possible is tied to the kernel stack size.

These seem fine for now, but we should maybe find a way to use something
besides g_kernel_stacks to set up the IST stacks if/when this becomes an
issue.
This commit is contained in:
Justin C. Miller
2021-02-02 18:27:37 -08:00
parent 8575939b20
commit 68a2250886
8 changed files with 166 additions and 87 deletions
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53
src/kernel/gdt.cpp
View File

@@ -4,6 +4,7 @@
#include "kutil/enum_bitfields.h"
#include "kutil/memory.h"
#include "console.h"
#include "kernel_memory.h"
#include "log.h"
@@ -136,19 +137,55 @@ idt_set_entry(uint8_t i, uint64_t addr, uint16_t selector, uint8_t flags)
}
void
tss_set_stack(int ring, uintptr_t rsp)
tss_set_stack(unsigned ring, uintptr_t rsp)
{
kassert(ring < 3, "Bad ring passed to tss_set_stack.");
g_tss.rsp[ring] = rsp;
}
uintptr_t
tss_get_stack(int ring)
tss_get_stack(unsigned ring)
{
kassert(ring < 3, "Bad ring passed to tss_get_stack.");
return g_tss.rsp[ring];
}
void
idt_set_ist(unsigned i, unsigned ist)
{
g_idt_table[i].ist = ist;
}
void
tss_set_ist(unsigned ist, uintptr_t rsp)
{
kassert(ist > 0 && ist < 7, "Bad ist passed to tss_set_ist.");
g_tss.ist[ist] = rsp;
}
void
ist_increment(unsigned i)
{
uint8_t ist = g_idt_table[i].ist;
if (ist)
g_tss.ist[ist] += memory::frame_size;
}
void
ist_decrement(unsigned i)
{
uint8_t ist = g_idt_table[i].ist;
if (ist)
g_tss.ist[ist] -= memory::frame_size;
}
uintptr_t
tss_get_ist(unsigned ist)
{
kassert(ist > 0 && ist < 7, "Bad ist passed to tss_get_ist.");
return g_tss.ist[ist];
}
void
gdt_init()
{
@@ -184,14 +221,14 @@ gdt_init()
}
void
gdt_dump(int index)
gdt_dump(unsigned index)
{
const table_ptr &table = g_gdtr;
console *cons = console::get();
int start = 0;
int count = (table.limit + 1) / sizeof(gdt_descriptor);
unsigned start = 0;
unsigned count = (table.limit + 1) / sizeof(gdt_descriptor);
if (index != -1) {
start = index;
count = 1;
@@ -240,13 +277,13 @@ gdt_dump(int index)
}
void
idt_dump(int index)
idt_dump(unsigned index)
{
const table_ptr &table = g_idtr;
int start = 0;
int count = (table.limit + 1) / sizeof(idt_descriptor);
unsigned start = 0;
unsigned count = (table.limit + 1) / sizeof(idt_descriptor);
if (index != -1) {
start = index;
count = 1;