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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen master] x86/trampoline: Rationalise the constants to describe the size
commit d2c214ede05cab1e56d99ceae0b2961a6b6d06ef
Author: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Nov 8 15:59:05 2024 +0000
Commit: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Nov 14 19:55:09 2024 +0000
x86/trampoline: Rationalise the constants to describe the size
The logic is far more sane to follow with a total size, and the position of
the end of the heap. Remove or fix the remaining descriptions of how the
trampoline is laid out.
Move the relevant constants into trampoline.h, which requires making the
header safe to include in assembly files.
No functional change. The compiled binary is identical.
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
xen/arch/x86/boot/head.S | 23 ++++-------------------
xen/arch/x86/boot/reloc.c | 5 ++---
xen/arch/x86/efi/efi-boot.h | 2 +-
xen/arch/x86/include/asm/config.h | 4 ----
xen/arch/x86/include/asm/trampoline.h | 7 +++++++
xen/arch/x86/xen.lds.S | 3 ++-
6 files changed, 16 insertions(+), 28 deletions(-)
diff --git a/xen/arch/x86/boot/head.S b/xen/arch/x86/boot/head.S
index dcda91cfda..1b3bd16fe5 100644
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -8,6 +8,8 @@
#include <asm/processor.h>
#include <asm/msr-index.h>
#include <asm/cpufeature.h>
+#include <asm/trampoline.h>
+
#include <public/elfnote.h>
#define ENTRY(name) \
@@ -494,7 +496,7 @@ trampoline_bios_setup:
2:
/* Reserve memory for the trampoline and the low-memory stack. */
- sub $((TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE)>>4),%ecx
+ sub $TRAMPOLINE_SIZE >> 4, %ecx
/* From arch/x86/smpboot.c: start_eip had better be page-aligned! */
xor %cl, %cl
@@ -525,23 +527,6 @@ trampoline_setup:
mov %eax, sym_esi(multiboot_ptr)
2:
- /*
- * Now trampoline_phys points to the following structure (lowest
address
- * is at the bottom):
- *
- * +------------------------+
- * | TRAMPOLINE_STACK_SPACE |
- * +------------------------+
- * | Data (MBI / PVH) |
- * +- - - - - - - - - - - - +
- * | TRAMPOLINE_SPACE |
- * +------------------------+
- *
- * Data grows downwards from the highest address of TRAMPOLINE_SPACE
- * region to the end of the trampoline. The rest of TRAMPOLINE_SPACE is
- * reserved for trampoline code and data.
- */
-
/* Interrogate CPU extended features via CPUID. */
mov $1, %eax
cpuid
@@ -713,7 +698,7 @@ trampoline_setup:
1:
/* Switch to low-memory stack which lives at the end of trampoline
region. */
mov sym_esi(trampoline_phys), %edi
- lea TRAMPOLINE_SPACE+TRAMPOLINE_STACK_SPACE(%edi),%esp
+ lea TRAMPOLINE_SIZE(%edi), %esp
lea trampoline_boot_cpu_entry-trampoline_start(%edi),%eax
pushl $BOOT_CS32
push %eax
diff --git a/xen/arch/x86/boot/reloc.c b/xen/arch/x86/boot/reloc.c
index e50e161b27..7a375ad41c 100644
--- a/xen/arch/x86/boot/reloc.c
+++ b/xen/arch/x86/boot/reloc.c
@@ -65,7 +65,7 @@ typedef struct memctx {
/*
* Simple bump allocator.
*
- * It starts from the base of the trampoline and allocates downwards.
+ * It starts from end of the trampoline heap and allocates downwards.
*/
uint32_t ptr;
} memctx;
@@ -349,8 +349,7 @@ static multiboot_info_t *mbi2_reloc(uint32_t mbi_in, memctx
*ctx)
/* SAF-1-safe */
void *reloc(uint32_t magic, uint32_t in)
{
- /* Get bottom-most low-memory stack address. */
- memctx ctx = { trampoline_phys + TRAMPOLINE_SPACE };
+ memctx ctx = { trampoline_phys + TRAMPOLINE_HEAP_END };
switch ( magic )
{
diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index 7930b7c738..9d3f2b7144 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -633,7 +633,7 @@ static void __init efi_arch_memory_setup(void)
if ( efi_enabled(EFI_LOADER) )
cfg.size = trampoline_end - trampoline_start;
else
- cfg.size = TRAMPOLINE_SPACE + TRAMPOLINE_STACK_SPACE;
+ cfg.size = TRAMPOLINE_SIZE;
status = efi_bs->AllocatePages(AllocateMaxAddress, EfiLoaderData,
PFN_UP(cfg.size), &cfg.addr);
diff --git a/xen/arch/x86/include/asm/config.h
b/xen/arch/x86/include/asm/config.h
index 84696e0a7d..19746f956e 100644
--- a/xen/arch/x86/include/asm/config.h
+++ b/xen/arch/x86/include/asm/config.h
@@ -51,10 +51,6 @@
#define IST_SHSTK_SIZE 1024
-#define TRAMPOLINE_STACK_SPACE PAGE_SIZE
-#define TRAMPOLINE_SPACE (KB(64) - TRAMPOLINE_STACK_SPACE)
-#define MBI_SPACE_MIN (2 * PAGE_SIZE)
-
/* Primary stack is restricted to 8kB by guard pages. */
#define PRIMARY_STACK_SIZE 8192
diff --git a/xen/arch/x86/include/asm/trampoline.h
b/xen/arch/x86/include/asm/trampoline.h
index fe69b723bd..0c508d0222 100644
--- a/xen/arch/x86/include/asm/trampoline.h
+++ b/xen/arch/x86/include/asm/trampoline.h
@@ -92,6 +92,12 @@
* boundaries, but are addresses as linked into Xen's .init section.
*/
+#define TRAMPOLINE_SIZE KB(64)
+#define TRAMPOLINE_HEAP_END (TRAMPOLINE_SIZE - PAGE_SIZE)
+#define MBI_SPACE_MIN (2 * PAGE_SIZE)
+
+#ifndef __ASSEMBLY__
+
#include <xen/compiler.h>
#include <xen/types.h>
@@ -162,4 +168,5 @@ extern uint8_t kbd_shift_flags;
extern uint16_t boot_edid_caps;
extern uint8_t boot_edid_info[128];
+#endif /* !__ASSEMBLY__ */
#endif /* X86_ASM_TRAMPOLINE_H */
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index 224b46771d..42217eaf24 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -9,6 +9,7 @@
#endif
#include <xen/xen.lds.h>
#include <asm/page.h>
+#include <asm/trampoline.h>
#ifdef EFI
@@ -420,5 +421,5 @@ ASSERT(!SIZEOF(.rela), "leftover relocations")
ASSERT((trampoline_perm_end - trampoline_start) <= 1024,
"Permentant trampoline too large")
-ASSERT((trampoline_end - trampoline_start) < TRAMPOLINE_SPACE - MBI_SPACE_MIN,
+ASSERT((trampoline_end - trampoline_start) < TRAMPOLINE_HEAP_END -
MBI_SPACE_MIN,
"not enough room for trampoline and mbi data")
--
generated by git-patchbot for /home/xen/git/xen.git#master
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