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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] x86/trampoline: Move the trampoline declarations out of <asm/config.h>
commit 65e4bc585c28b50ec76f679e1001a81fea9d690b
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Sep 4 13:27:03 2024 +0100
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Fri Sep 6 18:04:48 2024 +0100
x86/trampoline: Move the trampoline declarations out of <asm/config.h>
asm/config.h is included in every translation unit (via xen/config.h), while
only a handful of functions actually interact with the trampoline.
Move the infrastructure into its own header, and take the opportunity to
document everything.
Change trampoline_realmode_entry() and wakeup_start() to be nocall
functions,
rather than char arrays. Also switch to fixed width integers which are less
likely to diverge from the asm declaration.
No functional change.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/arch/x86/acpi/power.c | 2 +
xen/arch/x86/cpu/intel.c | 2 +
xen/arch/x86/efi/efi-boot.h | 1 +
xen/arch/x86/guest/xen/pvh-boot.c | 1 +
xen/arch/x86/include/asm/config.h | 19 -------
xen/arch/x86/include/asm/trampoline.h | 95 +++++++++++++++++++++++++++++++++++
xen/arch/x86/mm.c | 1 +
xen/arch/x86/platform_hypercall.c | 2 +
xen/arch/x86/setup.c | 1 +
xen/arch/x86/smpboot.c | 1 +
xen/arch/x86/tboot.c | 2 +
xen/arch/x86/x86_64/mm.c | 2 +
12 files changed, 110 insertions(+), 19 deletions(-)
diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 557faf312b..08a7fc2508 100644
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -31,6 +31,8 @@
#include <asm/microcode.h>
#include <asm/prot-key.h>
#include <asm/spec_ctrl.h>
+#include <asm/trampoline.h>
+
#include <acpi/cpufreq/cpufreq.h>
uint32_t system_reset_counter = 1;
diff --git a/xen/arch/x86/cpu/intel.c b/xen/arch/x86/cpu/intel.c
index af56e57bd8..807b708217 100644
--- a/xen/arch/x86/cpu/intel.c
+++ b/xen/arch/x86/cpu/intel.c
@@ -12,6 +12,8 @@
#include <asm/mpspec.h>
#include <asm/apic.h>
#include <asm/i387.h>
+#include <asm/trampoline.h>
+
#include <mach_apic.h>
#include "cpu.h"
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index f282358435..23e510c77e 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -9,6 +9,7 @@
#include <asm/microcode.h>
#include <asm/msr.h>
#include <asm/setup.h>
+#include <asm/trampoline.h>
static struct file __initdata ucode;
static multiboot_info_t __initdata mbi = {
diff --git a/xen/arch/x86/guest/xen/pvh-boot.c
b/xen/arch/x86/guest/xen/pvh-boot.c
index cc57ab2cbc..e14d7e20e9 100644
--- a/xen/arch/x86/guest/xen/pvh-boot.c
+++ b/xen/arch/x86/guest/xen/pvh-boot.c
@@ -12,6 +12,7 @@
#include <asm/e820.h>
#include <asm/guest.h>
+#include <asm/trampoline.h>
#include <public/arch-x86/hvm/start_info.h>
diff --git a/xen/arch/x86/include/asm/config.h
b/xen/arch/x86/include/asm/config.h
index 2a260a2581..1f828bfd52 100644
--- a/xen/arch/x86/include/asm/config.h
+++ b/xen/arch/x86/include/asm/config.h
@@ -83,25 +83,6 @@
#define LIST_POISON1 ((void *)0x0100100100100100UL)
#define LIST_POISON2 ((void *)0x0200200200200200UL)
-#ifndef __ASSEMBLY__
-extern unsigned long trampoline_phys;
-#define bootsym_phys(sym) \
- (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+trampoline_phys)
-#define bootsym(sym) \
- (*((typeof(sym) *)__va(bootsym_phys(sym))))
-
-extern char trampoline_start[], trampoline_end[];
-extern char trampoline_realmode_entry[];
-extern unsigned int trampoline_xen_phys_start;
-extern unsigned char trampoline_cpu_started;
-extern char wakeup_start[];
-
-extern unsigned char video_flags;
-
-extern unsigned short boot_edid_caps;
-extern unsigned char boot_edid_info[128];
-#endif
-
#include <xen/const.h>
#define PML4_ENTRY_BITS 39
diff --git a/xen/arch/x86/include/asm/trampoline.h
b/xen/arch/x86/include/asm/trampoline.h
new file mode 100644
index 0000000000..57a1f85a53
--- /dev/null
+++ b/xen/arch/x86/include/asm/trampoline.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef X86_ASM_TRAMPOLINE_H
+#define X86_ASM_TRAMPOLINE_H
+
+/*
+ * Data in or about the low memory trampoline.
+ *
+ * x86 systems software typically needs a block of logic below the 1M
+ * boundary, commonly called the trampoline, containing 16-bit logic. Xen has
+ * a combined trampoline of all necessary 16-bit logic, formed of two parts.
+ *
+ * 1) The permanent trampoline; a single 4k page containing:
+ *
+ * - The INIT-SIPI-SIPI entrypoint for APs, and
+ * - The S3 wakeup vector.
+ *
+ * Both of these are 16-bit entrypoints, responsible for activating paging
+ * and getting into 64-bit mode. This requires the permanent trampoline to
+ * be identity mapped in idle_pg_table[].
+ *
+ * The SIPI64 spec deprecates the 16-bit AP entrypoint, while S0ix (also
+ * called Low Power Idle or Connected Standby) deprecates S3.
+ *
+ * 2) The boot trampoline:
+ *
+ * This is used by the BSP to drop into 16-bit mode, make various BIOS
+ * calls to obtain E820/EDID/etc. It follows the permanent and exceeds 4k,
+ * but is only used in 16-bit and 32-bit unpaged mode so does not need
+ * mapping in pagetables.
+ *
+ * When the BIOS calls are complete, execution does join back with the AP
+ * path, and becomes subject to the same paging requirements. This path is
+ * not needed for non-BIOS boots.
+ *
+ * The location of trampoline is not fixed. The layout of low memory varies
+ * greatly from platform to platform. Therefore, the trampoline is relocated
+ * manually as part of placement.
+ */
+
+#include <xen/compiler.h>
+#include <xen/types.h>
+
+/*
+ * Start and end of the trampoline section, as linked into Xen. It is within
+ * the .init section and reclaimed after boot.
+ */
+/* SAF-0-safe */
+extern char trampoline_start[], trampoline_end[];
+
+/*
+ * The physical address of trampoline_start[] in low memory. It must be below
+ * the 1M boundary (as the trampoline contains 16-bit code), and must be 4k
+ * aligned (SIPI requirement for APs).
+ */
+extern unsigned long trampoline_phys;
+
+/*
+ * Calculate the physical address of a symbol in the trampoline.
+ *
+ * Should only be used on symbols declared later in this header. Specifying
+ * other symbols will compile but malfunction when used, as will using this
+ * helper before the trampoline is placed.
+ */
+#define bootsym_phys(sym) \
+ (trampoline_phys + ((unsigned long)&(sym) - \
+ (unsigned long)trampoline_start))
+
+/* Given a trampoline symbol, construct a pointer to it in the directmap. */
+#define bootsym(sym) (*((typeof(sym) *)__va(bootsym_phys(sym))))
+
+/* The INIT-SIPI-SIPI entrypoint. 16-bit code. */
+void nocall trampoline_realmode_entry(void);
+
+/* The S3 wakeup vector. 16-bit code. */
+void nocall wakeup_start(void);
+
+/*
+ * A variable in the trampoline, containing Xen's physical address. Amongst
+ * other things, it is used to find idle_pg_table[] in order to enable paging
+ * and activate 64-bit mode. This variable needs keeping in sync with
+ * xen_phys_start.
+ */
+extern uint32_t trampoline_xen_phys_start;
+
+/* A semaphore to indicate signs-of-life at the start of the AP boot path. */
+extern uint8_t trampoline_cpu_started;
+
+/* Quirks about video mode-setting on S3 resume. */
+extern uint8_t video_flags;
+
+/* Extended Display Identification Data, gathered from the BIOS. */
+extern uint16_t boot_edid_caps;
+extern uint8_t boot_edid_info[128];
+
+#endif /* X86_ASM_TRAMPOLINE_H */
diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 608583a113..c735aaf0e8 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -131,6 +131,7 @@
#include <asm/guest.h>
#include <asm/pv/domain.h>
#include <asm/pv/mm.h>
+#include <asm/trampoline.h>
#ifdef CONFIG_PV
#include "pv/mm.h"
diff --git a/xen/arch/x86/platform_hypercall.c
b/xen/arch/x86/platform_hypercall.c
index 7e32781093..67f851237d 100644
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -32,6 +32,8 @@
#include <asm/mtrr.h>
#include <asm/io_apic.h>
#include <asm/setup.h>
+#include <asm/trampoline.h>
+
#include "cpu/mcheck/mce.h"
#include "cpu/mtrr/mtrr.h"
#include <xsm/xsm.h>
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index cd69198326..a6e77c9ed9 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -59,6 +59,7 @@
#include <asm/microcode.h>
#include <asm/prot-key.h>
#include <asm/pv/domain.h>
+#include <asm/trampoline.h>
/* opt_nosmp: If true, secondary processors are ignored. */
static bool __initdata opt_nosmp;
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 0a89f22a39..9e79c1a6d6 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -35,6 +35,7 @@
#include <asm/spec_ctrl.h>
#include <asm/time.h>
#include <asm/tboot.h>
+#include <asm/trampoline.h>
#include <irq_vectors.h>
#include <mach_apic.h>
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index ba0700d2d5..d5db60d335 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -14,6 +14,8 @@
#include <asm/e820.h>
#include <asm/tboot.h>
#include <asm/setup.h>
+#include <asm/trampoline.h>
+
#include <crypto/vmac.h>
/* tboot=<physical address of shared page> */
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index b2a280fba3..0d8e602529 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -37,6 +37,8 @@ EMIT_FILE;
#include <asm/numa.h>
#include <asm/mem_paging.h>
#include <asm/mem_sharing.h>
+#include <asm/trampoline.h>
+
#include <public/memory.h>
#ifdef CONFIG_PV32
--
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