diff options
| author | Mark Johnston <markj@FreeBSD.org> | 2023-07-24 22:47:42 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2023-07-24 22:49:36 +0000 |
| commit | 789df254cc9e20c860ccc149b94dd1f92843ec9a (patch) | |
| tree | ae300ba6bead1583a79315b5a73b5b79975ca912 | |
| parent | 5b353925ff61b9ddb97bb453ba75278b578ed7d9 (diff) | |
| download | src-789df254cc9e20c860ccc149b94dd1f92843ec9a.tar.gz src-789df254cc9e20c860ccc149b94dd1f92843ec9a.zip | |
amd64: Use a larger boot stack
With sanitizers enabled, it becomes possible to overflow the stack when
only a single page is used. Follow arm64's example and use the default
kernel stack size instead. This is a bit wasteful, but without a guard
page, overflow merely corrupts adjacent .bss entries and is thus
difficult to debug.
Note, with a GENERIC kernel we already consume over half of the
available boot stack space, see the review for an example.
Reviewed by: kib
Reported by: Jenkins
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D41166
| -rw-r--r-- | sys/amd64/amd64/genassym.c | 1 | ||||
| -rw-r--r-- | sys/amd64/amd64/locore.S | 4 |
2 files changed, 3 insertions, 2 deletions
diff --git a/sys/amd64/amd64/genassym.c b/sys/amd64/amd64/genassym.c index feb3c7f503ce..4c17561b6e39 100644 --- a/sys/amd64/amd64/genassym.c +++ b/sys/amd64/amd64/genassym.c @@ -116,6 +116,7 @@ ASSYM(KERNBASE, KERNBASE); ASSYM(KERNLOAD, KERNLOAD); ASSYM(DMAP_MIN_ADDRESS, DMAP_MIN_ADDRESS); ASSYM(DMAP_MAX_ADDRESS, DMAP_MAX_ADDRESS); +ASSYM(KSTACK_PAGES, KSTACK_PAGES); ASSYM(PCB_R15, offsetof(struct pcb, pcb_r15)); ASSYM(PCB_R14, offsetof(struct pcb, pcb_r14)); diff --git a/sys/amd64/amd64/locore.S b/sys/amd64/amd64/locore.S index f034a25c9b1b..41386756021e 100644 --- a/sys/amd64/amd64/locore.S +++ b/sys/amd64/amd64/locore.S @@ -48,7 +48,7 @@ .set dmapbase,DMAP_MIN_ADDRESS .set dmapend,DMAP_MAX_ADDRESS -#define BOOTSTACK_SIZE 4096 +#define BOOTSTACK_SIZE (PAGE_SIZE * KSTACK_PAGES) .text /********************************************************************** @@ -148,7 +148,7 @@ ENTRY(la57_trampoline_gdt) ENTRY(la57_trampoline_end) .bss - ALIGN_DATA /* just to be sure */ + .p2align PAGE_SHIFT .globl bootstack .space BOOTSTACK_SIZE /* space for bootstack - temporary stack */ bootstack: |