riscv: vector: add a comment when calling riscv_setup_vsize()

AndybnACT · palmer-dabbelt · commit 77afe3e514b8 · 2024-05-30T14:33:04.000-07:00
The function would fail when it detects the calling hart's vlen doesn't match the first one's. The boot hart is the first hart calling this function during riscv_fill_hwcap, so it is impossible to fail here. Add a comment about this behavior. Signed-off-by: Andy Chiu <andy.chiu@sifive.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20240510-zve-detection-v5-1-0711bdd26c12@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
@@ -687,6 +687,9 @@ void __init riscv_fill_hwcap(void)
 	}
 
 	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+		/*
+		 * This cannot fail when called on the boot hart
+		 */
 		riscv_v_setup_vsize();
 		/*
 		 * ISA string in device tree might have 'v' flag, but

Original file line number	Diff line number	Diff line change
`@@ -687,6 +687,9 @@ void __init riscv_fill_hwcap(void)`
`687`	`687`	`}`
`688`	`688`
`689`	`689`	`if (elf_hwcap & COMPAT_HWCAP_ISA_V) {`
	`690`	`+ /*`
	`691`	`+ * This cannot fail when called on the boot hart`
	`692`	`+ */`
`690`	`693`	`riscv_v_setup_vsize();`
`691`	`694`	`/*`
`692`	`695`	`* ISA string in device tree might have 'v' flag, but`