system/freebsd-src
system/freebsd-src
1
0
Fork 0
mirror of https://github.com/freebsd/freebsd-src synced 2024-10-01 14:14:56 +00:00
Code Issues Packages Projects Releases Wiki Activity

riscv: improve commentary around initial stvec

Browse source 
Make it explicit why we must set the trap vector before enabling virtual
memory.

Reviewed by:	br, jhb, markj
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D45474
This commit is contained in:
Mitchell Horne 2024-06-03 14:24:12 -03:00
parent 3ff981587f
commit 134f7b5fa9
1 changed files with 12 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

16
sys/riscv/riscv/locore.S
View file

@ -197,7 +197,11 @@ pagetables:
/* Page tables END */
/* Setup supervisor trap vector */
/*
* Set the supervisor trap vector temporarily. Enabling virtual memory
* may generate a page fault. We simply wish to continue onwards, so
* have the trap deliver us to 'va'.
*/
2:
lla t0, va
sub t0, t0, s9
@ -221,7 +225,7 @@ va:
lla gp, __global_pointer$
.option pop
/* Setup supervisor trap vector */
/* Set the trap vector to the real handler. */
la t0, cpu_exception_handler
csrw stvec, t0
@ -342,7 +346,11 @@ ENTRY(mpentry)
/* Get the kernel's load address */
jal get_physmem
/* Setup supervisor trap vector */
/*
* Set the supervisor trap vector temporarily. Enabling virtual memory
* may generate a page fault. We simply wish to continue onwards, so
* have the trap deliver us to 'mpva'.
*/
lla t0, mpva
sub t0, t0, s9
li t1, KERNBASE
@ -365,7 +373,7 @@ mpva:
lla gp, __global_pointer$
.option pop
/* Setup supervisor trap vector */
/* Set the trap vector to the real handler. */
la t0, cpu_exception_handler
csrw stvec, t0