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Map framebuffer with write-combining access mode to speed up physical hardware

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This commit is contained in:
Josh Holtrop 2024-07-29 00:01:47 -04:00
parent 26bb071b4d
commit 30aedfc97b
3 changed files with 8 additions and 2 deletions
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1
src/hulk/cpu.d
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@ -57,6 +57,7 @@ enum ulong XCR0_PKRU = 0x100u;
/** @} */ /** @} */
/** MSR register numbers. @{ */ /** MSR register numbers. @{ */
enum uint MSR_PAT = 0x277u;
enum uint MSR_EFER = 0xC000_0080u; enum uint MSR_EFER = 0xC000_0080u;
/** @} */ /** @} */

6
src/hulk/hurl/hurl.d
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@ -91,7 +91,7 @@ struct Hurl
map_range(HULK_FRAMEBUFFER, map_range(HULK_FRAMEBUFFER,
cast(ulong)header.bootinfo.fb.buffer, cast(ulong)header.bootinfo.fb.buffer,
header.bootinfo.fb.height * header.bootinfo.fb.stride * 4u, header.bootinfo.fb.height * header.bootinfo.fb.stride * 4u,
PT_WRITABLE | PT_NO_EXECUTE); PT_PAT | PT_WRITABLE | PT_NO_EXECUTE);
/* Map framebuffer buffer1. */ /* Map framebuffer buffer1. */
map_range(cast(ulong)header.bootinfo.fb_buffer1_phys, map_range(cast(ulong)header.bootinfo.fb_buffer1_phys,
cast(ulong)header.bootinfo.fb_buffer1_phys, cast(ulong)header.bootinfo.fb_buffer1_phys,
@ -197,6 +197,10 @@ struct Hurl
} }
} }
/* Set PAT4 to indicate Write Combining so we can set the PAT bit in a
* page table entry to use Write Combining for that page. */
wrmsr(MSR_PAT, (rdmsr(MSR_PAT) & 0xFFFF_FF00_FFFF_FFFFu) | 0x0000_0001_0000_0000u);
/* /*
* Now that we have available physical pages to allocate from, we can * Now that we have available physical pages to allocate from, we can
* build new page tables to replace the bootloader page tables. * build new page tables to replace the bootloader page tables.

3
src/hulk/pagetable.d
View File

@ -11,7 +11,8 @@ enum ulong PT_WRITE_THROUGH = 0x8u;
enum ulong PT_DISABLE_CACHE = 0x10u; enum ulong PT_DISABLE_CACHE = 0x10u;
enum ulong PT_ACCESSED = 0x20u; enum ulong PT_ACCESSED = 0x20u;
enum ulong PT_DIRTY = 0x40u; enum ulong PT_DIRTY = 0x40u;
enum ulong PT_HUGE_PAGE = 0x80u; enum ulong PT_PAT = 0x80u; /* Page table entry bit. */
enum ulong PT_HUGE_PAGE = 0x80u; /* Page directory entry bit. */
enum ulong PT_GLOBAL = 0x100u; enum ulong PT_GLOBAL = 0x100u;
enum ulong PT_NO_EXECUTE = 0x8000_0000_0000_0000u; enum ulong PT_NO_EXECUTE = 0x8000_0000_0000_0000u;
/** @} */ /** @} */