diff options
| author | Vladimir Serbinenko <phcoder@gmail.com> | 2014-02-05 19:46:45 +0100 |
|---|---|---|
| committer | Vladimir Serbinenko <phcoder@gmail.com> | 2014-02-25 00:57:35 +0100 |
| commit | 4337020b950454815204eed4e43a894be0b125ca (patch) | |
| tree | 7aa3a4ad420a54b3079f3216d577aafab1bca2e0 /src/include/cpu/x86 | |
| parent | 20f83d56561879045ecade24d51e79dfb151baf6 (diff) | |
Remove CACHE_ROM.
With the recent improvement 3d6ffe76f8a505c2dff5d5c6146da3d63dad6e82,
speedup by CACHE_ROM is reduced a lot.
On the other hand this makes coreboot run out of MTRRs depending on
system configuration, hence screwing up I/O access and cache
coherency in worst cases.
CACHE_ROM requires the user to sanity check their boot output because
the feature is brittle. The working configuration is dependent on I/O
hole size, ram size, and chipset. Because of this the current
implementation can leave a system configured in an inconsistent state
leading to unexpected results such as poor performance and/or
inconsistent cache-coherency
Remove this as a buggy feature until we figure out how to do it properly
if necessary.
Change-Id: I858d78a907bf042fcc21fdf7a2bf899e9f6b591d
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/5146
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
Diffstat (limited to 'src/include/cpu/x86')
| -rw-r--r-- | src/include/cpu/x86/mtrr.h | 23 |
1 files changed, 0 insertions, 23 deletions
diff --git a/src/include/cpu/x86/mtrr.h b/src/include/cpu/x86/mtrr.h index 9414687552..2a440723b8 100644 --- a/src/include/cpu/x86/mtrr.h +++ b/src/include/cpu/x86/mtrr.h @@ -52,10 +52,6 @@ * of the nature of the global MTRR enable flag. Therefore, all direct * or indirect callers of enable_fixed_mtrr() should ensure that the * variable MTRR MSRs do not contain bad ranges. - * 3. If CONFIG_CACHE_ROM is selected an MTRR is allocated for enabling - * the caching of the ROM. However, it is set to uncacheable (UC). It - * is the responsibility of the caller to enable it by calling - * x86_mtrr_enable_rom_caching(). */ void x86_setup_mtrrs(void); /* @@ -71,25 +67,6 @@ void x86_setup_fixed_mtrrs(void); /* Set up fixed MTRRs but do not enable them. */ void x86_setup_fixed_mtrrs_no_enable(void); int x86_mtrr_check(void); -/* ROM caching can be used after variable MTRRs are set up. Beware that - * enabling CONFIG_CACHE_ROM will eat through quite a few MTRRs based on - * one's IO hole size and WRCOMB resources. Be sure to check the console - * log when enabling CONFIG_CACHE_ROM or adding WRCOMB resources. Beware that - * on CPUs with core-scoped MTRR registers such as hyperthreaded CPUs the - * rom caching will be disabled if all threads run the MTRR code. Therefore, - * one needs to call x86_mtrr_enable_rom_caching() after all threads of the - * same core have run the MTRR code. */ -#if CONFIG_CACHE_ROM -void x86_mtrr_enable_rom_caching(void); -void x86_mtrr_disable_rom_caching(void); -/* Return the variable range MTRR index of the ROM cache. */ -long x86_mtrr_rom_cache_var_index(void); -#else -static inline void x86_mtrr_enable_rom_caching(void) {} -static inline void x86_mtrr_disable_rom_caching(void) {} -static inline long x86_mtrr_rom_cache_var_index(void) { return -1; } -#endif /* CONFIG_CACHE_ROM */ - #endif #if !defined(__ASSEMBLER__) && defined(__PRE_RAM__) && !defined(__ROMCC__) |