Re: [PATCH v15 3/6] x86/boot: Introduce efi_get_rsdp_addr() to find RSDP from EFI table

Borislav Petkov
2019-01-11T10:32:36Z

On Fri, Jan 11, 2019 at 09:23:53AM +0800, Chao Fan wrote:
> Yes, 'table64' looks superfluous here, but after these lines, there is:
> if (!IS_ENABLED(CONFIG_X86_64) && table64 >> 32) {
> so the 'table64' is useful here for i386. 'table' is unsigned long, it
> can't do the right shift. But the 'table64' who is u64 can do that right
> shift.

Have you actually tried fixing what I suggested or you're just talking?

---
diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c
index e9dd84f459ed..0537d46fb21f 100644
--- a/arch/x86/boot/compressed/acpi.c
+++ b/arch/x86/boot/compressed/acpi.c
@@ -77,21 +77,19 @@ static acpi_physical_address efi_get_rsdp_addr(void)
sizeof(efi_config_table_32_t);

for (i = 0; i < systab->nr_tables; i++) {
+ acpi_physical_address table;
void *config_tables;
- unsigned long table;
efi_guid_t guid;

config_tables = (void *)(systab->tables + size * i);
if (efi_64) {
efi_config_table_64_t *tmp_table;
- u64 table64;

tmp_table = config_tables;
guid = tmp_table->guid;
- table64 = tmp_table->table;
- table = table64;
+ table = tmp_table->table;

- if (!IS_ENABLED(CONFIG_X86_64) && table64 >> 32) {
+ if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
return 0;
}

--
Regards/Gruss,
Boris.

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