Use write-combining MTRR to speed up video with buggy BIOSes.
* grub-core/video/i386/pc/vbe.c (framebuffer): New member mtrr. (cpuid): New define. (rdmsr): Likewise. (wrmsr): Likewise. (mtrr_base): Likewise. (mtrr_mask): Likewise. (grub_vbe_enable_mtrr_entry): New function. (grub_vbe_enable_mtrr): Likewise. (grub_vbe_disable_mtrr): Likewise. (grub_vbe_bios_set_display_start): Disable mtrr when handing the control off to BIOS. (grub_video_vbe_init): Fill mtrr. (grub_video_vbe_fini): Disable mtrr. (grub_video_vbe_get_info_and_fini): Likewise. (grub_video_vbe_setup): Enable mtrr.
This commit is contained in:
Colin Watson
Vladimir 'phcoder' Serbinenko
parent
e3c78337c3
commit
cfe456dc03
2 changed files with 214 additions and 2 deletions
20
ChangeLog
20
ChangeLog
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@ -1,3 +1,23 @@
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2012-02-27 Colin Watson <cjwatson@ubuntu.com>
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Use write-combining MTRR to speed up video with buggy BIOSes.
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* grub-core/video/i386/pc/vbe.c (framebuffer): New member mtrr.
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(cpuid): New define.
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(rdmsr): Likewise.
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(wrmsr): Likewise.
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(mtrr_base): Likewise.
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(mtrr_mask): Likewise.
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(grub_vbe_enable_mtrr_entry): New function.
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(grub_vbe_enable_mtrr): Likewise.
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(grub_vbe_disable_mtrr): Likewise.
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(grub_vbe_bios_set_display_start): Disable mtrr when handing the
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control off to BIOS.
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(grub_video_vbe_init): Fill mtrr.
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(grub_video_vbe_fini): Disable mtrr.
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(grub_video_vbe_get_info_and_fini): Likewise.
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(grub_video_vbe_setup): Enable mtrr.
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2012-02-27 Colin Watson <cjwatson@ubuntu.com>
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* include/grub/partition.h (grub_partition_map): Change prototype of
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@ -29,6 +29,7 @@
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#include <grub/video.h>
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#include <grub/i386/pc/int.h>
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#include <grub/i18n.h>
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#include <grub/cpu/tsc.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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@ -44,6 +45,7 @@ static struct
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struct grub_video_mode_info mode_info;
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grub_uint8_t *ptr;
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int mtrr;
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} framebuffer;
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static grub_uint32_t initial_vbe_mode;
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@ -56,6 +58,171 @@ real2pm (grub_vbe_farptr_t ptr)
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+ ((unsigned long) ptr & 0x0000FFFF));
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}
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#define cpuid(num,a,b,c,d) \
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asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
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: "=a" (a), "=r" (b), "=c" (c), "=d" (d) \
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: "0" (num))
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#define rdmsr(num,a,d) \
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asm volatile ("rdmsr" : "=a" (a), "=d" (d) : "c" (num))
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#define wrmsr(num,lo,hi) \
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asm volatile ("wrmsr" : : "c" (num), "a" (lo), "d" (hi) : "memory")
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#define mtrr_base(reg) (0x200 + (reg) * 2)
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#define mtrr_mask(reg) (0x200 + (reg) * 2 + 1)
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/* Try to set up a variable-range write-combining MTRR for a memory region.
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This is best-effort; if it seems too hard, we just accept the performance
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degradation rather than risking undefined behaviour. It is intended
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exclusively to work around BIOS bugs, as the BIOS should already be
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setting up a suitable MTRR. */
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static void
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grub_vbe_enable_mtrr_entry (int mtrr)
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{
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grub_uint32_t eax, edx;
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grub_uint32_t mask_lo, mask_hi;
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rdmsr (mtrr_mask (mtrr), eax, edx);
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mask_lo = eax;
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mask_hi = edx;
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mask_lo |= 0x800 /* valid */;
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wrmsr (mtrr_mask (mtrr), mask_lo, mask_hi);
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}
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static void
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grub_vbe_enable_mtrr (grub_uint8_t *base, grub_size_t size)
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{
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grub_uint32_t eax, ebx, ecx, edx;
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grub_uint32_t features;
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grub_uint32_t mtrrcap;
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int var_mtrrs;
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grub_uint32_t max_extended_cpuid;
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grub_uint32_t maxphyaddr;
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grub_uint64_t fb_base, fb_size;
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grub_uint64_t size_bits, fb_mask;
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grub_uint32_t bits_lo, bits_hi;
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grub_uint64_t bits;
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int i, first_unused = -1;
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grub_uint32_t base_lo, base_hi, mask_lo, mask_hi;
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fb_base = (grub_uint64_t) (grub_size_t) base;
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fb_size = (grub_uint64_t) size;
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/* Check that fb_base and fb_size can be represented using a single
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MTRR. */
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if (fb_base < (1 << 20))
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return; /* under 1MB, so covered by fixed-range MTRRs */
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if (fb_base >= (1LL << 36))
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return; /* over 36 bits, so out of range */
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if (fb_size < (1 << 12))
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return; /* variable-range MTRRs must cover at least 4KB */
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size_bits = fb_size;
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while (size_bits > 1)
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size_bits >>= 1;
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if (size_bits != 1)
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return; /* not a power of two */
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if (fb_base & (fb_size - 1))
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return; /* not aligned on size boundary */
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fb_mask = ~(fb_size - 1);
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/* Check CPU capabilities. */
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if (! grub_cpu_is_cpuid_supported ())
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return;
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cpuid (1, eax, ebx, ecx, edx);
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features = edx;
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if (! (features & 0x00001000)) /* MTRR */
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return;
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rdmsr (0xFE, eax, edx);
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mtrrcap = eax;
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if (! (mtrrcap & 0x00000400)) /* write-combining */
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return;
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var_mtrrs = (mtrrcap & 0xFF);
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cpuid (0x80000000, eax, ebx, ecx, edx);
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max_extended_cpuid = eax;
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if (max_extended_cpuid >= 0x80000008)
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{
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cpuid (0x80000008, eax, ebx, ecx, edx);
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maxphyaddr = (eax & 0xFF);
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}
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else
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maxphyaddr = 36;
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bits_lo = 0xFFFFF000; /* assume maxphyaddr >= 36 */
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bits_hi = (1 << (maxphyaddr - 32)) - 1;
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bits = bits_lo | ((grub_uint64_t) bits_hi << 32);
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/* Check whether an MTRR already covers this region. If not, take an
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unused one if possible. */
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for (i = 0; i < var_mtrrs; i++)
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{
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rdmsr (mtrr_mask (i), eax, edx);
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mask_lo = eax;
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mask_hi = edx;
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if (mask_lo & 0x800) /* valid */
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{
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grub_uint64_t real_base, real_mask;
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rdmsr (mtrr_base (i), eax, edx);
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base_lo = eax;
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base_hi = edx;
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real_base = ((grub_uint64_t) (base_hi & bits_hi) << 32) |
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(base_lo & bits_lo);
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real_mask = ((grub_uint64_t) (mask_hi & bits_hi) << 32) |
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(mask_lo & bits_lo);
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if (real_base < (fb_base + fb_size) &&
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real_base + (~real_mask & bits) >= fb_base)
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return; /* existing MTRR overlaps this region */
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}
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else if (first_unused < 0)
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first_unused = i;
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}
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if (first_unused < 0)
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return; /* all MTRRs in use */
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/* Set up the first unused MTRR we found. */
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rdmsr (mtrr_base (first_unused), eax, edx);
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base_lo = eax;
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base_hi = edx;
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rdmsr (mtrr_mask (first_unused), eax, edx);
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mask_lo = eax;
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mask_hi = edx;
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base_lo = (base_lo & ~bits_lo & ~0xFF) |
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(fb_base & bits_lo) | 0x01 /* WC */;
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base_hi = (base_hi & ~bits_hi) | ((fb_base >> 32) & bits_hi);
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wrmsr (mtrr_base (first_unused), base_lo, base_hi);
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mask_lo = (mask_lo & ~bits_lo) | (fb_mask & bits_lo) | 0x800 /* valid */;
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mask_hi = (mask_hi & ~bits_hi) | ((fb_mask >> 32) & bits_hi);
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wrmsr (mtrr_mask (first_unused), mask_lo, mask_hi);
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framebuffer.mtrr = first_unused;
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}
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static void
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grub_vbe_disable_mtrr (int mtrr)
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{
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grub_uint32_t eax, edx;
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grub_uint32_t mask_lo, mask_hi;
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rdmsr (mtrr_mask (mtrr), eax, edx);
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mask_lo = eax;
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mask_hi = edx;
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mask_lo &= ~0x800 /* valid */;
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wrmsr (mtrr_mask (mtrr), mask_lo, mask_hi);
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}
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/* Call VESA BIOS 0x4f09 to set palette data, return status. */
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static grub_vbe_status_t
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grub_vbe_bios_set_palette_data (grub_uint32_t color_count,
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@ -221,6 +388,9 @@ grub_vbe_bios_set_display_start (grub_uint32_t x, grub_uint32_t y)
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{
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struct grub_bios_int_registers regs;
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if (framebuffer.mtrr >= 0)
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grub_vbe_disable_mtrr (framebuffer.mtrr);
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/* Store x in %ecx. */
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regs.ecx = x;
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regs.edx = y;
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@ -229,6 +399,10 @@ grub_vbe_bios_set_display_start (grub_uint32_t x, grub_uint32_t y)
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regs.ebx = 0x0080;
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regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
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grub_bios_interrupt (0x10, ®s);
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if (framebuffer.mtrr >= 0)
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grub_vbe_enable_mtrr_entry (framebuffer.mtrr);
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return regs.eax & 0xffff;
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}
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@ -325,7 +499,6 @@ grub_vbe_bios_read_edid (struct grub_video_edid_info *edid_info)
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return regs.eax & 0xffff;
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}
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grub_err_t
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grub_vbe_probe (struct grub_vbe_info_block *info_block)
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{
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@ -630,6 +803,7 @@ grub_video_vbe_init (void)
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/* Reset frame buffer. */
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grub_memset (&framebuffer, 0, sizeof(framebuffer));
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framebuffer.mtrr = -1;
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return grub_video_fb_init ();
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}
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@ -655,6 +829,11 @@ grub_video_vbe_fini (void)
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vbe_mode_list = NULL;
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err = grub_video_fb_fini ();
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if (framebuffer.mtrr >= 0)
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{
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grub_vbe_disable_mtrr (framebuffer.mtrr);
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framebuffer.mtrr = -1;
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}
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return err;
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}
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@ -956,6 +1135,10 @@ grub_video_vbe_setup (unsigned int width, unsigned int height,
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/* Copy default palette to initialize emulated palette. */
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err = grub_video_fb_set_palette (0, GRUB_VIDEO_FBSTD_NUMCOLORS,
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grub_video_fbstd_colors);
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grub_vbe_enable_mtrr (framebuffer.ptr,
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controller_info.total_memory << 16);
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return err;
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}
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@ -986,9 +1169,18 @@ static grub_err_t
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grub_video_vbe_get_info_and_fini (struct grub_video_mode_info *mode_info,
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void **framebuf)
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{
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grub_err_t err;
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grub_free (vbe_mode_list);
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vbe_mode_list = NULL;
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return grub_video_fb_get_info_and_fini (mode_info, framebuf);
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err = grub_video_fb_get_info_and_fini (mode_info, framebuf);
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if (err)
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return err;
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if (framebuffer.mtrr >= 0)
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{
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grub_vbe_disable_mtrr (framebuffer.mtrr);
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framebuffer.mtrr = -1;
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}
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return GRUB_ERR_NONE;
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}
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static void
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