linux-kernel - Re: [PATCH] Fix VMI crash on boot in 2.6.27+ kernels

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Message-ID: <49405CB6.6010006@kernel.org>
Date:	Wed, 10 Dec 2008 16:20:06 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Zachary Amsden <zach@...are.com>
CC:	Huang Ying <ying.huang@...el.com>,
	Jeremy Fitzhardinge <jeremy@...p.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"norman@...backs.co.uk" <norman@...backs.co.uk>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Greg KH <gregkh@...e.de>,
	Alok Kataria <alokkataria1@...il.com>,
	Bruno Prémont <"bruno .premont"@restena.lu>,
	"xl@...igned.net" <xl@...igned.net>,
	"dsd@...too.org" <dsd@...too.org>
Subject: Re: [PATCH] Fix VMI crash on boot in 2.6.27+ kernels

Zachary Amsden wrote:
> On Tue, 2008-12-09 at 17:15 -0800, Yinghai Lu wrote:
> 
>> you can not move that late,
>>
>> parse_setup_data==>early_memremap==>__early_ioremap
> 
> How does this look?
> 

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 9d5674f..4c381cb 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -794,6 +794,11 @@ void __init setup_arch(char **cmdline_p)
 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
 #endif
 
+#ifdef CONFIG_VMI
+	/* VMI may relocate the fixmap; do this before touching ioremap area */
+	vmi_init();
+#endif
+
 	early_cpu_init();
 	early_ioremap_init();
 
@@ -880,12 +885,9 @@ void __init setup_arch(char **cmdline_p)
 	check_efer();
 #endif
 
-#if defined(CONFIG_VMI) && defined(CONFIG_X86_32)
-	/*
-	 * Must be before kernel pagetables are setup
-	 * or fixmap area is touched.
-	 */
-	vmi_init();
+#if defined(CONFIG_VMI)
+	/* Must be before kernel pagetables are setup */
+	vmi_activate();
 #endif
 
 	/* after early param, so could get panic from serial */
diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 8b6c393..22fd657 100644
--- a/arch/x86/kernel/vmi_32.c
+++ b/arch/x86/kernel/vmi_32.c
@@ -960,8 +960,6 @@ static inline int __init activate_vmi(void)
 
 void __init vmi_init(void)
 {
-	unsigned long flags;
-
 	if (!vmi_rom)
 		probe_vmi_rom();
 	else
@@ -973,13 +971,21 @@ void __init vmi_init(void)
 
 	reserve_top_address(-vmi_rom->virtual_top);


it seems still have some problem.
you moved reserve_top_address before parse_parameter...

so
void __init reserve_top_address(unsigned long reserve)
{
        BUG_ON(fixmaps_set > 0);
        printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",
               (int)-reserve);
        __FIXADDR_TOP = -reserve - PAGE_SIZE;
        __VMALLOC_RESERVE += reserve;
}

/*
 * vmalloc=size forces the vmalloc area to be exactly 'size'
 * bytes. This can be used to increase (or decrease) the
 * vmalloc area - the default is 128m.
 */
static int __init parse_vmalloc(char *arg)
{
        if (!arg)
                return -EINVAL;

        /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
        __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
        return 0;
}
early_param("vmalloc", parse_vmalloc);

__VMALLOC_RESERVE will be overwriten by vmalloc=...

you may need to split reserve_top_address() to two functions...

YH

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