[PATCH 1/2] x86/acpi: add retrieval function for rsdp address

From: Juergen Gross
Date: Thu Jan 25 2018 - 05:05:23 EST


Add a function to get the address of the RSDP table. Per default use a
__weak annotated function being a nop.

Cc: <stable@xxxxxxxxxxxxxxx> # 4.11
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
drivers/acpi/osl.c | 10 +++++++++-
include/linux/acpi.h | 2 ++
2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3bb46cb24a99..2b77db914752 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -178,6 +178,11 @@ void acpi_os_vprintf(const char *fmt, va_list args)
#endif
}

+__weak acpi_physical_address acpi_arch_get_root_pointer(void)
+{
+ return 0;
+}
+
#ifdef CONFIG_KEXEC
static unsigned long acpi_rsdp;
static int __init setup_acpi_rsdp(char *arg)
@@ -189,12 +194,15 @@ early_param("acpi_rsdp", setup_acpi_rsdp);

acpi_physical_address __init acpi_os_get_root_pointer(void)
{
- acpi_physical_address pa = 0;
+ acpi_physical_address pa;

#ifdef CONFIG_KEXEC
if (acpi_rsdp)
return acpi_rsdp;
#endif
+ pa = acpi_arch_get_root_pointer();
+ if (pa)
+ return pa;

if (efi_enabled(EFI_CONFIG_TABLES)) {
if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index dc1ebfeeb5ec..aa603cc5ad30 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1266,4 +1266,6 @@ static inline int lpit_read_residency_count_address(u64 *address)
}
#endif

+acpi_physical_address acpi_arch_get_root_pointer(void);
+
#endif /*_LINUX_ACPI_H*/
--
2.13.6