Commit d891b921 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/mm/pat: Clean up PAT initialization flags 



Right now we have these variables that impact the PAT initialization sequence:

  pat_disabled
  boot_cpu_done
  pat_initialized
  init_cm_done

Some have a pat_ prefix, some not, and the naming is random,
which makes their purpose rather opaque.

Name them consistently and according to their role:

  pat_disabled
  pat_bp_initialized
  pat_bp_enabled
  pat_cm_initialized

Also rename pat_bsp_init() => pat_bp_init(), to use the canonical
abbreviation.

Also add a warning for double calls of init_cache_modes(), the call chains
leading to this are complex and I couldn't convince myself that we never
call this function twice - so utilize the flag for a debug check.

No change in functionality intended.

Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent baf65855

arch/x86/mm/pat.c

+14 −12
Original line number Diff line number Diff line
@@ -61,10 +61,10 @@ 
#undef pr_fmt

#define pr_fmt(fmt) "" fmt



static bool __read_mostly boot_cpu_done;

static bool __read_mostly pat_bp_initialized;

static bool __read_mostly pat_disabled = !IS_ENABLED(CONFIG_X86_PAT);

static bool __read_mostly pat_initialized;

static bool __read_mostly init_cm_done;

static bool __read_mostly pat_bp_enabled;

static bool __read_mostly pat_cm_initialized;



/*

 * PAT support is enabled by default, but can be disabled for
@@ -75,7 +75,7 @@ void pat_disable(const char *msg_reason) 
	if (pat_disabled)

		return;



	if (boot_cpu_done) {

	if (pat_bp_initialized) {

		WARN_ONCE(1, "x86/PAT: PAT cannot be disabled after initialization\n");

		return;

	}
@@ -93,7 +93,7 @@ early_param("nopat", nopat); 


bool pat_enabled(void)

{

	return pat_initialized;

	return pat_bp_enabled;

}

EXPORT_SYMBOL_GPL(pat_enabled);
@@ -224,6 +224,8 @@ static void __init_cache_modes(u64 pat) 
	char pat_msg[33];

	int i;



	WARN_ON_ONCE(pat_cm_initialized);



	pat_msg[32] = 0;

	for (i = 7; i >= 0; i--) {

		cache = pat_get_cache_mode((pat >> (i * 8)) & 7,
@@ -232,12 +234,12 @@ static void __init_cache_modes(u64 pat) 
	}

	pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg);



	init_cm_done = true;

	pat_cm_initialized = true;

}



#define PAT(x, y)	((u64)PAT_ ## y << ((x)*8))



static void pat_bsp_init(u64 pat)

static void pat_bp_init(u64 pat)

{

	u64 tmp_pat;
@@ -253,7 +255,7 @@ static void pat_bsp_init(u64 pat) 
	}



	wrmsrl(MSR_IA32_CR_PAT, pat);

	pat_initialized = true;

	pat_bp_enabled = true;



	__init_cache_modes(pat);

}
@@ -275,7 +277,7 @@ void init_cache_modes(void) 
{

	u64 pat = 0;



	if (init_cm_done)

	if (pat_cm_initialized)

		return;



	if (boot_cpu_has(X86_FEATURE_PAT)) {
@@ -395,9 +397,9 @@ void pat_init(void) 
		      PAT(4, WB) | PAT(5, WP) | PAT(6, UC_MINUS) | PAT(7, WT);

	}



	if (!boot_cpu_done) {

		pat_bsp_init(pat);

		boot_cpu_done = true;

	if (!pat_bp_initialized) {

		pat_bp_init(pat);

		pat_bp_initialized = true;

	} else {

		pat_ap_init(pat);

	}

CRA Git | Maintained and supported by SUSTech CRA and CCSE