diff options
Diffstat (limited to 'src/arch')
| -rw-r--r-- | src/arch/x86/include/bits/errfile.h | 1 | ||||
| -rw-r--r-- | src/arch/x86/interface/pcbios/rtc_entropy.c | 56 |
2 files changed, 57 insertions, 0 deletions
diff --git a/src/arch/x86/include/bits/errfile.h b/src/arch/x86/include/bits/errfile.h index 42792242d..79b6f882e 100644 --- a/src/arch/x86/include/bits/errfile.h +++ b/src/arch/x86/include/bits/errfile.h @@ -23,6 +23,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #define ERRFILE_vesafb ( ERRFILE_ARCH | ERRFILE_CORE | 0x000c0000 ) #define ERRFILE_int13con ( ERRFILE_ARCH | ERRFILE_CORE | 0x000d0000 ) #define ERRFILE_gdbmach ( ERRFILE_ARCH | ERRFILE_CORE | 0x000e0000 ) +#define ERRFILE_rtc_entropy ( ERRFILE_ARCH | ERRFILE_CORE | 0x000f0000 ) #define ERRFILE_bootsector ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00000000 ) #define ERRFILE_bzimage ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00010000 ) diff --git a/src/arch/x86/interface/pcbios/rtc_entropy.c b/src/arch/x86/interface/pcbios/rtc_entropy.c index 83c2445f8..e9e6baa59 100644 --- a/src/arch/x86/interface/pcbios/rtc_entropy.c +++ b/src/arch/x86/interface/pcbios/rtc_entropy.c @@ -31,17 +31,26 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); #include <stdint.h> #include <string.h> +#include <errno.h> +#include <unistd.h> #include <biosint.h> #include <pic8259.h> #include <rtc.h> #include <ipxe/entropy.h> +/** Maximum time to wait for an RTC interrupt, in milliseconds */ +#define RTC_MAX_WAIT_MS 100 + /** RTC interrupt handler */ extern void rtc_isr ( void ); /** Previous RTC interrupt handler */ static struct segoff rtc_old_handler; +/** Flag set by RTC interrupt handler */ +extern volatile uint8_t __text16 ( rtc_flag ); +#define rtc_flag __use_text16 ( rtc_flag ) + /** * Hook RTC interrupt handler * @@ -96,6 +105,10 @@ static void rtc_unhook_isr ( void ) { static void rtc_enable_int ( void ) { uint8_t status_b; + /* Clear any stale pending interrupts via status register C */ + outb ( ( RTC_STATUS_C | CMOS_DISABLE_NMI ), CMOS_ADDRESS ); + inb ( CMOS_DATA ); + /* Set Periodic Interrupt Enable bit in status register B */ outb ( ( RTC_STATUS_B | CMOS_DISABLE_NMI ), CMOS_ADDRESS ); status_b = inb ( CMOS_DATA ); @@ -126,17 +139,59 @@ static void rtc_disable_int ( void ) { } /** + * Check that entropy gathering is functional + * + * @ret rc Return status code + */ +static int rtc_entropy_check ( void ) { + unsigned int i; + + /* Check that RTC interrupts are working */ + rtc_flag = 0; + for ( i = 0 ; i < RTC_MAX_WAIT_MS ; i++ ) { + + /* Allow interrupts to occur */ + __asm__ __volatile__ ( "sti\n\t" + "nop\n\t" + "nop\n\t" + "cli\n\t" ); + + /* Check for RTC interrupt flag */ + if ( rtc_flag ) + return 0; + + /* Delay */ + mdelay ( 1 ); + } + + DBGC ( &rtc_flag, "RTC timed out waiting for interrupt\n" ); + return -ETIMEDOUT; +} + +/** * Enable entropy gathering * * @ret rc Return status code */ static int rtc_entropy_enable ( void ) { + int rc; + /* Hook ISR and enable RTC interrupts */ rtc_hook_isr(); enable_irq ( RTC_IRQ ); rtc_enable_int(); + /* Check that RTC interrupts are working */ + if ( ( rc = rtc_entropy_check() ) != 0 ) + goto err_check; + return 0; + + err_check: + rtc_disable_int(); + disable_irq ( RTC_IRQ ); + rtc_unhook_isr(); + return rc; } /** @@ -145,6 +200,7 @@ static int rtc_entropy_enable ( void ) { */ static void rtc_entropy_disable ( void ) { + /* Disable RTC interrupts and unhook ISR */ rtc_disable_int(); disable_irq ( RTC_IRQ ); rtc_unhook_isr(); |