Currently we only support Vector for SMP platforms, that is, all SMP cores have the same vlenb. If we happen to detect a mismatching vlen, it is better to just fail bootting it up to prevent further race/scheduling issues.
Also, move .Lsecondary_park forward and chage `tail smp_callin` into a regular call in the early assembly. So a core would be parked right after a return from smp_callin. Note that a successful smp_callin does not return.
Fixes: 7017858eb2d7 ("riscv: Introduce riscv_v_vsize to record size of Vector context") Reported-by: Conor Dooley conor.dooley@microchip.com Closes: https://lore.kernel.org/linux-riscv/20240228-vicinity-cornstalk-4b8eb5fe5730... Signed-off-by: Andy Chiu andy.chiu@sifive.com --- Changelog v4: - update comment also in the assembly code (Yunhui) Changelog v2: - update commit message to explain asm code change (Conor) --- arch/riscv/kernel/head.S | 19 ++++++++++++------- arch/riscv/kernel/smpboot.c | 14 +++++++++----- 2 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 4236a69c35cb..a00f7523cb91 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -165,9 +165,20 @@ secondary_start_sbi: #endif call .Lsetup_trap_vector scs_load_current - tail smp_callin + call smp_callin #endif /* CONFIG_SMP */
+.align 2 +.Lsecondary_park: + /* + * Park this hart if we: + * - have too many harts on CONFIG_RISCV_BOOT_SPINWAIT + * - receive an early trap, before setup_trap_vector finished + * - fail in smp_callin(), as a successful one wouldn't return + */ + wfi + j .Lsecondary_park + .align 2 .Lsetup_trap_vector: /* Set trap vector to exception handler */ @@ -181,12 +192,6 @@ secondary_start_sbi: csrw CSR_SCRATCH, zero ret
-.align 2 -.Lsecondary_park: - /* We lack SMP support or have too many harts, so park this hart */ - wfi - j .Lsecondary_park - SYM_CODE_END(_start)
SYM_CODE_START(_start_kernel) diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c index d41090fc3203..673437ccc13d 100644 --- a/arch/riscv/kernel/smpboot.c +++ b/arch/riscv/kernel/smpboot.c @@ -214,6 +214,15 @@ asmlinkage __visible void smp_callin(void) struct mm_struct *mm = &init_mm; unsigned int curr_cpuid = smp_processor_id();
+ if (has_vector()) { + /* + * Return as early as possible so the hart with a mismatching + * vlen won't boot. + */ + if (riscv_v_setup_vsize()) + return; + } + /* All kernel threads share the same mm context. */ mmgrab(mm); current->active_mm = mm; @@ -226,11 +235,6 @@ asmlinkage __visible void smp_callin(void) numa_add_cpu(curr_cpuid); set_cpu_online(curr_cpuid, 1);
- if (has_vector()) { - if (riscv_v_setup_vsize()) - elf_hwcap &= ~COMPAT_HWCAP_ISA_V; - } - riscv_user_isa_enable();
/*