linux-kernel - [PATCH v3 2/2] x86, espfix: init espfix on the boot cpu side

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Message-ID: <c97add2670e9abebb90095369f0cfc172373ac94.1435824469.git.zhugh.fnst@cn.fujitsu.com>
Date:	Fri, 3 Jul 2015 17:37:19 +0800
From:	Zhu Guihua <zhugh.fnst@...fujitsu.com>
To:	<linux-kernel@...r.kernel.org>
CC:	<mingo@...nel.org>, <hpa@...or.com>, <luto@...capital.net>,
	<luto@...nel.org>, <bp@...en8.de>, <tglx@...utronix.de>,
	<x86@...nel.org>, Zhu Guihua <zhugh.fnst@...fujitsu.com>
Subject: [PATCH v3 2/2] x86, espfix: init espfix on the boot cpu side

As we alloc pages with GFP_KERNEL in init_espfix_ap() which is called
before enabled local irq, the lockdep sub-system would trigger a warning.

So we allocate them on the boot CPU side when the target CPU is bringing
up by the primary CPU, and hand them over to the secondary CPU.

And we use alloc_pages_node() with the secondary CPU's node, to make sure
the espfix stack is NUMA-local to the CPU that is going to use it.

Signed-off-by: Zhu Guihua <zhugh.fnst@...fujitsu.com>
---
 arch/x86/kernel/espfix_64.c | 21 +++++++++++++--------
 arch/x86/kernel/smpboot.c   | 14 +++++++-------
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c
index 1fb0e00..ce95676 100644
--- a/arch/x86/kernel/espfix_64.c
+++ b/arch/x86/kernel/espfix_64.c
@@ -141,12 +141,12 @@ void init_espfix_ap(int cpu)
 	pud_t pud, *pud_p;
 	pmd_t pmd, *pmd_p;
 	pte_t pte, *pte_p;
-	int n;
+	int n, node;
 	void *stack_page;
 	pteval_t ptemask;
 
 	/* We only have to do this once... */
-	if (likely(this_cpu_read(espfix_stack)))
+	if (likely(per_cpu(espfix_stack, cpu)))
 		return;		/* Already initialized */
 
 	addr = espfix_base_addr(cpu);
@@ -164,12 +164,15 @@ void init_espfix_ap(int cpu)
 	if (stack_page)
 		goto unlock_done;
 
+	node = cpu_to_node(cpu);
 	ptemask = __supported_pte_mask;
 
 	pud_p = &espfix_pud_page[pud_index(addr)];
 	pud = *pud_p;
 	if (!pud_present(pud)) {
-		pmd_p = (pmd_t *)__get_free_page(PGALLOC_GFP);
+		struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0);
+
+		pmd_p = (pmd_t *)page_address(page);
 		pud = __pud(__pa(pmd_p) | (PGTABLE_PROT & ptemask));
 		paravirt_alloc_pmd(&init_mm, __pa(pmd_p) >> PAGE_SHIFT);
 		for (n = 0; n < ESPFIX_PUD_CLONES; n++)
@@ -179,7 +182,9 @@ void init_espfix_ap(int cpu)
 	pmd_p = pmd_offset(&pud, addr);
 	pmd = *pmd_p;
 	if (!pmd_present(pmd)) {
-		pte_p = (pte_t *)__get_free_page(PGALLOC_GFP);
+		struct page *page = alloc_pages_node(node, PGALLOC_GFP, 0);
+
+		pte_p = (pte_t *)page_address(page);
 		pmd = __pmd(__pa(pte_p) | (PGTABLE_PROT & ptemask));
 		paravirt_alloc_pte(&init_mm, __pa(pte_p) >> PAGE_SHIFT);
 		for (n = 0; n < ESPFIX_PMD_CLONES; n++)
@@ -187,7 +192,7 @@ void init_espfix_ap(int cpu)
 	}
 
 	pte_p = pte_offset_kernel(&pmd, addr);
-	stack_page = (void *)__get_free_page(GFP_KERNEL);
+	stack_page = page_address(alloc_pages_node(node, GFP_KERNEL, 0));
 	pte = __pte(__pa(stack_page) | (__PAGE_KERNEL_RO & ptemask));
 	for (n = 0; n < ESPFIX_PTE_CLONES; n++)
 		set_pte(&pte_p[n*PTE_STRIDE], pte);
@@ -198,7 +203,7 @@ void init_espfix_ap(int cpu)
 unlock_done:
 	mutex_unlock(&espfix_init_mutex);
 done:
-	this_cpu_write(espfix_stack, addr);
-	this_cpu_write(espfix_waddr, (unsigned long)stack_page
-		       + (addr & ~PAGE_MASK));
+	per_cpu(espfix_stack, cpu) = addr;
+	per_cpu(espfix_waddr, cpu) = (unsigned long)stack_page
+				      + (addr & ~PAGE_MASK);
 }
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 6f5abac..0bd8c1d 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -239,13 +239,6 @@ static void notrace start_secondary(void *unused)
 	check_tsc_sync_target();
 
 	/*
-	 * Enable the espfix hack for this CPU
-	 */
-#ifdef CONFIG_X86_ESPFIX64
-	init_espfix_ap(smp_processor_id());
-#endif
-
-	/*
 	 * We need to hold vector_lock so there the set of online cpus
 	 * does not change while we are assigning vectors to cpus.  Holding
 	 * this lock ensures we don't half assign or remove an irq from a cpu.
@@ -854,6 +847,13 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
 	initial_code = (unsigned long)start_secondary;
 	stack_start  = idle->thread.sp;
 
+	/*
+	 * Enable the espfix hack for this CPU
+	*/
+#ifdef CONFIG_X86_ESPFIX64
+	init_espfix_ap(cpu);
+#endif
+
 	/* So we see what's up */
 	announce_cpu(cpu, apicid);
 
-- 
1.9.3

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