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x86/boot: Reposition trampoline data
... to separate code from data. In particular, trampoline_realmode_entry's write to trampoline_cpu_started clobbers the I-cache line containing trampoline_protmode_entry, which won't be great for AP startup performance. Reformat the comments for trampoline_gdt to reduce their volume. No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com>
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Andrew Cooper committed
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a6a2705c66
1 file changed
+29
-40
@@ -58,46 +58,6 @@ GLOBAL(trampoline_realmode_entry)
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ljmpl $BOOT_CS32,$bootsym_rel(trampoline_protmode_entry,6)
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trampoline_gdt:
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/* 0x0000: unused */
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.quad 0x0000000000000000
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/* 0x0008: ring 0 code, 32-bit mode */
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.quad 0x00cf9b000000ffff
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/* 0x0010: ring 0 code, 64-bit mode */
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.quad 0x00af9b000000ffff
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/* 0x0018: ring 0 data */
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.quad 0x00cf93000000ffff
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/* 0x0020: real-mode code @ BOOT_TRAMPOLINE */
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.long 0x0000ffff
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.long 0x00009b00
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/* 0x0028: real-mode data @ BOOT_TRAMPOLINE */
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.long 0x0000ffff
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.long 0x00009300
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/*
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* 0x0030: ring 0 Xen data, 16 MiB size, base
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* address is computed at runtime.
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*/
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.quad 0x00c0930000000fff
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.Ltrampoline_gdt_end:
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.pushsection .trampoline_rel, "a"
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.long trampoline_gdt + BOOT_PSEUDORM_CS + 2 - .
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.long trampoline_gdt + BOOT_PSEUDORM_DS + 2 - .
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.popsection
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GLOBAL(trampoline_misc_enable_off)
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.quad 0
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/* EFER OR-mask for boot paths. This gets adjusted with NX when available. */
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GLOBAL(trampoline_efer)
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.long EFER_LME | EFER_SCE
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GLOBAL(trampoline_xen_phys_start)
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.long 0
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GLOBAL(trampoline_cpu_started)
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.byte 0
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.code32
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trampoline_protmode_entry:
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/* Set up a few descriptors: on entry only CS is guaranteed good. */
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@@ -183,6 +143,35 @@ idt_48: .word 0, 0, 0 # base = limit = 0
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gdt_48: .word .Ltrampoline_gdt_end - trampoline_gdt - 1
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.long bootsym_rel(trampoline_gdt,4)
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trampoline_gdt:
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.quad 0x0000000000000000 /* 0x0000: unused */
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.quad 0x00cf9b000000ffff /* 0x0008: ring 0 code, 32-bit mode */
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.quad 0x00af9b000000ffff /* 0x0010: ring 0 code, 64-bit mode */
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.quad 0x00cf93000000ffff /* 0x0018: ring 0 data */
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.quad 0x00009b000000ffff /* 0x0020: real-mode code @ BOOT_TRAMPOLINE */
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.quad 0x000093000000ffff /* 0x0028: real-mode data @ BOOT_TRAMPOLINE */
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.quad 0x00c0930000000fff /* 0x0030: ring 0 Xen data, 16M @ XEN */
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.Ltrampoline_gdt_end:
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/* Relocations for trampoline Real Mode segments. */
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.pushsection .trampoline_rel, "a"
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.long trampoline_gdt + BOOT_PSEUDORM_CS + 2 - .
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.long trampoline_gdt + BOOT_PSEUDORM_DS + 2 - .
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.popsection
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GLOBAL(trampoline_misc_enable_off)
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.quad 0
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/* EFER OR-mask for boot paths. This gets adjusted with NX when available. */
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GLOBAL(trampoline_efer)
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.long EFER_LME | EFER_SCE
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GLOBAL(trampoline_xen_phys_start)
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.long 0
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GLOBAL(trampoline_cpu_started)
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.byte 0
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/* The first page of trampoline is permanent, the rest boot-time only. */
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/* Reuse the boot trampoline on the 1st trampoline page as stack for wakeup. */
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.equ wakeup_stack, trampoline_start + PAGE_SIZE
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