Message-Id: <1482113266-13207-6-git-send-email-fancer.lancer@gmail.com>
Date:   Mon, 19 Dec 2016 05:07:30 +0300
From:   Serge Semin <fancer.lancer@...il.com>
To:     ralf@...ux-mips.org, paul.burton@...tec.com, rabinv@...s.com,
        matt.redfearn@...tec.com, james.hogan@...tec.com,
        alexander.sverdlin@...ia.com, robh+dt@...nel.org,
        frowand.list@...il.com
Cc:     Sergey.Semin@...latforms.ru, linux-mips@...ux-mips.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Serge Semin <fancer.lancer@...il.com>
Subject: [PATCH 05/21] MIPS memblock: Alter initrd memory reservation method

Since memblock is used, initrd memory region can be easily
verified and reserved if looks ok. Verification method will be
useful for other reservation methods.

Signed-off-by: Serge Semin <fancer.lancer@...il.com>
---
 arch/mips/kernel/setup.c | 157 ++++++++++++++++-------------
 1 file changed, 87 insertions(+), 70 deletions(-)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 789aafe..d2f38ac 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -82,6 +82,8 @@ static struct resource data_resource = { .name = "Kernel data", };
 
 static void *detect_magic __initdata = detect_memory_region;
 
+static phys_addr_t __initdata mips_lowmem_limit;
+
 /*
  * General method to add RAM regions to the system
  *
@@ -266,6 +268,38 @@ static int __init early_parse_mem(char *p)
 early_param("mem", early_parse_mem);
 
 /*
+ * Helper method checking whether passed lowmem region is valid
+ */
+static bool __init is_lowmem_and_valid(const char *name, phys_addr_t base,
+				       phys_addr_t size)
+{
+	phys_addr_t end = base + size;
+
+	/* Check whether region belongs to actual memory */
+	if (!memblock_is_region_memory(base, size)) {
+		pr_err("%s %08zx @ %pa is not a memory region", name,
+			(size_t)size, &base);
+		return false;
+	}
+
+	/* Check whether region belongs to low memory */
+	if (end > mips_lowmem_limit) {
+		pr_err("%s %08zx @ %pa is out of low memory", name,
+			(size_t)size, &base);
+	       return false;
+	}
+
+	/* Check whether region is free */
+	if (memblock_is_region_reserved(base, size)) {
+		pr_err("%s %08zx @ %pa overlaps in-use memory", name,
+			(size_t)size, &base);
+		return false;
+	}
+
+	return true;
+}
+
+/*
  * Manage initrd
  */
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -292,47 +326,6 @@ static int __init rd_size_early(char *p)
 }
 early_param("rd_size", rd_size_early);
 
-/* it returns the next free pfn after initrd */
-static unsigned long __init init_initrd(void)
-{
-	unsigned long end;
-
-	/*
-	 * Board specific code or command line parser should have
-	 * already set up initrd_start and initrd_end. In these cases
-	 * perfom sanity checks and use them if all looks good.
-	 */
-	if (!initrd_start || initrd_end <= initrd_start)
-		goto disable;
-
-	if (initrd_start & ~PAGE_MASK) {
-		pr_err("initrd start must be page aligned\n");
-		goto disable;
-	}
-	if (initrd_start < PAGE_OFFSET) {
-		pr_err("initrd start < PAGE_OFFSET\n");
-		goto disable;
-	}
-
-	/*
-	 * Sanitize initrd addresses. For example firmware
-	 * can't guess if they need to pass them through
-	 * 64-bits values if the kernel has been built in pure
-	 * 32-bit. We need also to switch from KSEG0 to XKPHYS
-	 * addresses now, so the code can now safely use __pa().
-	 */
-	end = __pa(initrd_end);
-	initrd_end = (unsigned long)__va(end);
-	initrd_start = (unsigned long)__va(__pa(initrd_start));
-
-	ROOT_DEV = Root_RAM0;
-	return PFN_UP(end);
-disable:
-	initrd_start = 0;
-	initrd_end = 0;
-	return 0;
-}
-
 /* In some conditions (e.g. big endian bootloader with a little endian
    kernel), the initrd might appear byte swapped.  Try to detect this and
    byte swap it if needed.  */
@@ -362,26 +355,64 @@ static void __init maybe_bswap_initrd(void)
 #endif
 }
 
-static void __init finalize_initrd(void)
+/*
+ * Check and reserve memory occupied by initrd
+ */
+static void __init mips_reserve_initrd_mem(void)
 {
-	unsigned long size = initrd_end - initrd_start;
+	phys_addr_t phys_initrd_start, phys_initrd_end, phys_initrd_size;
 
-	if (size == 0) {
-		printk(KERN_INFO "Initrd not found or empty");
+	/*
+	 * Board specific code or command line parser should have already set
+	 * up initrd_start and initrd_end. In these cases perform sanity checks
+	 * and use them if all looks good.
+	 */
+	if (!initrd_start || initrd_end <= initrd_start) {
+		pr_info("No initrd found");
 		goto disable;
 	}
-	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
-		printk(KERN_ERR "Initrd extends beyond end of memory");
+	if (initrd_start & ~PAGE_MASK) {
+		pr_err("Initrd start must be page aligned");
 		goto disable;
 	}
+	if (initrd_start < PAGE_OFFSET) {
+		pr_err("Initrd start < PAGE_OFFSET");
+		goto disable;
+	}
+
+	/*
+	 * Sanitize initrd addresses. For example firmware can't guess if they
+	 * need to pass them through 64-bits values if the kernel has been
+	 * built in pure 32-bit. We need also to switch from KSEG0 to XKPHYS
+	 * addresses now, so the code can now safely use __pa().
+	 */
+	phys_initrd_start = __pa(initrd_start);
+	phys_initrd_end = __pa(initrd_end);
+	phys_initrd_size = phys_initrd_end - phys_initrd_start;
 
+	/* Check whether initrd region is within available lowmem and free */
+	if (!is_lowmem_and_valid("Initrd", phys_initrd_start, phys_initrd_size))
+		goto disable;
+
+	/* Initrd may be byteswapped in Octeon */
 	maybe_bswap_initrd();
 
-	reserve_bootmem(__pa(initrd_start), size, BOOTMEM_DEFAULT);
+	/* Memory for initrd can be reserved now */
+	memblock_reserve(phys_initrd_start, phys_initrd_size);
+
+	/* Convert initrd to virtual addresses back (needed for x32 -> x64) */
+	initrd_start = (unsigned long)__va(phys_initrd_start);
+	initrd_end = (unsigned long)__va(phys_initrd_end);
+
+	/* It's OK to have initrd below actual memory start. Really? */
 	initrd_below_start_ok = 1;
 
-	pr_info("Initial ramdisk at: 0x%lx (%lu bytes)\n",
-		initrd_start, size);
+	pr_info("Initial ramdisk at: 0x%lx (%zu bytes)\n",
+		initrd_start, (size_t)phys_initrd_size);
+
+	/* Set root device to be first ram disk */
+	ROOT_DEV = Root_RAM0;
+
 	return;
 disable:
 	printk(KERN_CONT " - disabling initrd\n");
@@ -391,12 +422,7 @@ disable:
 
 #else  /* !CONFIG_BLK_DEV_INITRD */
 
-static unsigned long __init init_initrd(void)
-{
-	return 0;
-}
-
-#define finalize_initrd()	do {} while (0)
+static void __init mips_reserve_initrd_mem(void) { }
 
 #endif
 
@@ -408,8 +434,8 @@ static unsigned long __init init_initrd(void)
 
 static void __init bootmem_init(void)
 {
-	init_initrd();
-	finalize_initrd();
+	/* Check and reserve memory occupied by initrd */
+	mips_reserve_initrd_mem();
 }
 
 #else  /* !CONFIG_SGI_IP27 */
@@ -421,13 +447,9 @@ static void __init bootmem_init(void)
 	unsigned long bootmap_size;
 	int i;
 
-	/*
-	 * Sanity check any INITRD first. We don't take it into account
-	 * for bootmem setup initially, rely on the end-of-kernel-code
-	 * as our memory range starting point. Once bootmem is inited we
-	 * will reserve the area used for the initrd.
-	 */
-	init_initrd();
+	/* Check and reserve memory occupied by initrd */
+	mips_reserve_initrd_mem();
+
 	reserved_end = (unsigned long) PFN_UP(__pa_symbol(&_end));
 
 	/*
@@ -618,11 +640,6 @@ static void __init bootmem_init(void)
 #endif
 	}
 #endif
-
-	/*
-	 * Reserve initrd memory if needed.
-	 */
-	finalize_initrd();
 }
 
 #endif	/* CONFIG_SGI_IP27 */
-- 
2.6.6

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