Message ID | 20230327164941.20491-17-andy.chiu@sifive.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | riscv: Add vector ISA support | expand |
Am Montag, 27. März 2023, 18:49:36 CEST schrieb Andy Chiu: > From: Greentime Hu <greentime.hu@sifive.com> > > Early function calls, such as setup_vm(), relocate_enable_mmu(), > soc_early_init() etc, are free to operate on stack. However, > PT_SIZE_ON_STACK bytes at the head of the kernel stack are purposedly > reserved for the placement of per-task register context pointed by > task_pt_regs(p). Those functions may corrupt task_pt_regs if we overlap > the $sp with it. In fact, we had accidentally corrupted sstatus.VS in some > tests, treating the kernel to save V context before V was actually > allocated, resulting in a kernel panic. > > Thus, we should skip PT_SIZE_ON_STACK for $sp before making C function > calls from the top-level assembly. > > Co-developed-by: ShihPo Hung <shihpo.hung@sifive.com> > Signed-off-by: ShihPo Hung <shihpo.hung@sifive.com> > Co-developed-by: Vincent Chen <vincent.chen@sifive.com> > Signed-off-by: Vincent Chen <vincent.chen@sifive.com> > Signed-off-by: Greentime Hu <greentime.hu@sifive.com> > Signed-off-by: Andy Chiu <andy.chiu@sifive.com> > Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu> Tested-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index e16bb2185d55..11c3b94c4534 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -301,6 +301,7 @@ clear_bss_done: la tp, init_task la sp, init_thread_union + THREAD_SIZE XIP_FIXUP_OFFSET sp + addi sp, sp, -PT_SIZE_ON_STACK #ifdef CONFIG_BUILTIN_DTB la a0, __dtb_start XIP_FIXUP_OFFSET a0 @@ -318,6 +319,7 @@ clear_bss_done: /* Restore C environment */ la tp, init_task la sp, init_thread_union + THREAD_SIZE + addi sp, sp, -PT_SIZE_ON_STACK #ifdef CONFIG_KASAN call kasan_early_init