[efi] Add EFI image format and basic runtime environment

We have EFI APIs for CPU I/O, PCI I/O, timers, console I/O, user access and user memory allocation. EFI executables are created using the vanilla GNU toolchain, with the EXE header handcrafted in assembly and relocations generated by a custom efilink utility.
2026-01-09 13:42:25 +03:00 · 2008-10-12 01:55:55 +01:00
parent 54c024e0af
commit 81d92c6d34
40 changed files with 4781 additions and 1 deletions
--- a/src/interface/efi/efi_timer.c
+++ b/src/interface/efi/efi_timer.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <limits.h>
+#include <assert.h>
+#include <unistd.h>
+#include <gpxe/timer.h>
+#include <gpxe/efi/efi.h>
+#include <gpxe/efi/Protocol/Cpu.h>
+
+/** @file
+ *
+ * gPXE timer API for EFI
+ *
+ */
+
+/** Scale factor to apply to CPU timer 0
+ *
+ * The timer is scaled down in order to ensure that reasonable values
+ * for "number of ticks" don't exceed the size of an unsigned long.
+ */
+#define EFI_TIMER0_SHIFT 12
+
+/** Calibration time */
+#define EFI_CALIBRATE_DELAY_MS 1
+
+/** CPU protocol */
+static EFI_CPU_ARCH_PROTOCOL *cpu_arch;
+EFI_REQUIRE_PROTOCOL ( EFI_CPU_ARCH_PROTOCOL, &cpu_arch );
+
+/**
+ * Delay for a fixed number of microseconds
+ *
+ * @v usecs		Number of microseconds for which to delay
+ */
+static void efi_udelay ( unsigned long usecs ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_STATUS efirc;
+
+	if ( ( efirc = bs->Stall ( usecs ) ) != 0 ) {
+		DBG ( "EFI could not delay for %ldus: %lx\n",
+		      usecs, efirc );
+		/* Probably screwed */
+	}
+}
+
+/**
+ * Get current system time in ticks
+ *
+ * @ret ticks		Current time, in ticks
+ */
+static unsigned long efi_currticks ( void ) {
+	UINT64 time;
+	EFI_STATUS efirc;
+
+	/* Read CPU timer 0 (TSC) */
+	if ( ( efirc = cpu_arch->GetTimerValue ( cpu_arch, 0, &time,
+						 NULL ) ) != 0 ) {
+		DBG ( "EFI could not read CPU timer: %lx\n", efirc );
+		/* Probably screwed */
+		return -1UL;
+	}
+
+	return ( time >> EFI_TIMER0_SHIFT );
+}
+
+/**
+ * Get number of ticks per second
+ *
+ * @ret ticks_per_sec	Number of ticks per second
+ */
+static unsigned long efi_ticks_per_sec ( void ) {
+	static unsigned long ticks_per_sec = 0;
+
+	/* Calibrate timer, if necessary.  EFI does nominally provide
+	 * the timer speed via the (optional) TimerPeriod parameter to
+	 * the GetTimerValue() call, but it gets the speed slightly
+	 * wrong.  By up to three orders of magnitude.  Not helpful.
+	 */
+	if ( ! ticks_per_sec ) {
+		unsigned long start;
+		unsigned long elapsed;
+
+		DBG ( "Calibrating EFI timer with a %d ms delay\n",
+		      EFI_CALIBRATE_DELAY_MS );
+		start = currticks();
+		mdelay ( EFI_CALIBRATE_DELAY_MS );
+		elapsed = ( currticks() - start );
+		ticks_per_sec = ( elapsed * ( 1000 / EFI_CALIBRATE_DELAY_MS ));
+		DBG ( "EFI CPU timer calibrated at %ld ticks in %d ms (%ld "
+		      "ticks/sec)\n", elapsed, EFI_CALIBRATE_DELAY_MS,
+		      ticks_per_sec );
+	}
+
+	return ticks_per_sec;
+}
+
+PROVIDE_TIMER ( efi, udelay, efi_udelay );
+PROVIDE_TIMER ( efi, currticks, efi_currticks );
+PROVIDE_TIMER ( efi, ticks_per_sec, efi_ticks_per_sec );