When CMOS RTC Not Present git set in FADT, system should not access CMOS
interface for time. This patch move get/set rtc time function from CMOS
to EFI runtime on x86_64 machine. And, it also set the BUG_ON check in
rtc_cmos_read/write function to avoid access it.
Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx>
---
arch/x86/kernel/rtc.c | 8 ++++++++
include/asm-generic/rtc.h | 22 ++++++++++++++++++++++
2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
index 9b6c568..a54cd09 100644
--- a/arch/x86/kernel/rtc.c
+++ b/arch/x86/kernel/rtc.c
@@ -117,6 +117,10 @@ unsigned char rtc_cmos_read(unsigned char addr)
{
unsigned char val;
+ BUG_ON(acpi_gbl_FADT.header.revision >= 5 &&
+ acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC &&
+ addr <= RTC_YEAR);
+
lock_cmos_prefix(addr);
outb(addr, RTC_PORT(0));
val = inb(RTC_PORT(1));
@@ -128,6 +132,10 @@ EXPORT_SYMBOL(rtc_cmos_read);
void rtc_cmos_write(unsigned char val, unsigned char addr)
{
+ BUG_ON(acpi_gbl_FADT.header.revision >= 5 &&
+ acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC &&
+ addr <= RTC_YEAR);
+
lock_cmos_prefix(addr);
outb(addr, RTC_PORT(0));
outb(val, RTC_PORT(1));
diff --git a/include/asm-generic/rtc.h b/include/asm-generic/rtc.h
index fa86f24..4ba8aa6 100644
--- a/include/asm-generic/rtc.h
+++ b/include/asm-generic/rtc.h
@@ -16,6 +16,8 @@
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/delay.h>
+#include <linux/efi.h>
+#include <linux/acpi.h>
#define RTC_PIE 0x40 /* periodic interrupt enable */
#define RTC_AIE 0x20 /* alarm interrupt enable */
@@ -51,6 +53,16 @@ static inline unsigned int __get_rtc_time(struct rtc_time *time)
unsigned int real_year;
#endif
+ if (acpi_gbl_FADT.header.revision >= 5 &&
+ acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
+ printk_once(KERN_INFO "efi: get rtc time by EFI\n");
+ return efi_read_time(time);
+#else
+ BUG();
+#endif
+ }
+
/*
* read RTC once any update in progress is done. The update
* can take just over 2ms. We wait 20ms. There is no need to
@@ -123,6 +135,16 @@ static inline int __set_rtc_time(struct rtc_time *time)
unsigned int real_yrs, leap_yr;
#endif
+ if (acpi_gbl_FADT.header.revision >= 5 &&
+ acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
+#if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
+ printk_once(KERN_INFO "efi: set rtc time by EFI\n");
+ return efi_set_time(time);
+#else
+ BUG();
+#endif
+ }
+
yrs = time->tm_year;
mon = time->tm_mon + 1; /* tm_mon starts at zero */
day = time->tm_mday;
--
1.6.4.2
--
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