Unverified Commit 4400231c authored Jul 15, 2020 by Atish Patra Committed by Palmer Dabbelt Jul 24, 2020

RISC-V: Do not rely on initrd_start/end computed during early dt parsing



Currently, initrd_start/end are computed during early_init_dt_scan
but used during arch_setup. We will get the following panic if initrd is used
and CONFIG_DEBUG_VIRTUAL is turned on.

[    0.000000] ------------[ cut here ]------------
[    0.000000] kernel BUG at arch/riscv/mm/physaddr.c:33!
[    0.000000] Kernel BUG [#1]
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-rc4-00015-ged0b226fed02 #886
[    0.000000] epc: ffffffe0002058d2 ra : ffffffe0000053f0 sp : ffffffe001001f40
[    0.000000]  gp : ffffffe00106e250 tp : ffffffe001009d40 t0 : ffffffe00107ee28
[    0.000000]  t1 : 0000000000000000 t2 : ffffffe000a2e880 s0 : ffffffe001001f50
[    0.000000]  s1 : ffffffe0001383e8 a0 : ffffffe00c087e00 a1 : 0000000080200000
[    0.000000]  a2 : 00000000010bf000 a3 : ffffffe00106f3c8 a4 : ffffffe0010bf000
[    0.000000]  a5 : ffffffe000000000 a6 : 0000000000000006 a7 : 0000000000000001
[    0.000000]  s2 : ffffffe00106f068 s3 : ffffffe00106f070 s4 : 0000000080200000
[    0.000000]  s5 : 0000000082200000 s6 : 0000000000000000 s7 : 0000000000000000
[    0.000000]  s8 : 0000000080011010 s9 : 0000000080012700 s10: 0000000000000000
[    0.000000]  s11: 0000000000000000 t3 : 000000000001fe30 t4 : 000000000001fe30
[    0.000000]  t5 : 0000000000000000 t6 : ffffffe00107c471
[    0.000000] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003
[    0.000000] random: get_random_bytes called from print_oops_end_marker+0x22/0x46 with crng_init=0

To avoid the error, initrd_start/end can be computed from phys_initrd_start/size
in setup itself. It also improves the initrd placement by aligning the start
and size with the page size.

Fixes: 76d2a049 ("RISC-V: Init and Halt Code")
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

parent d0d8aae6

arch/riscv/mm/init.c

+27 −6

Original line number	Diff line number	Diff line
		@@ -95,19 +95,40 @@ void __init mem_init(void)
		#ifdef CONFIG_BLK_DEV_INITRD
		static void __init setup_initrd(void)
		{
		phys_addr_t start;
		unsigned long size;

		if (initrd_start >= initrd_end) {
		pr_info("initrd not found or empty");
		/* Ignore the virtul address computed during device tree parsing */
		initrd_start = initrd_end = 0;

		if (!phys_initrd_size)
		return;
		/*
		* Round the memory region to page boundaries as per free_initrd_mem()
		* This allows us to detect whether the pages overlapping the initrd
		* are in use, but more importantly, reserves the entire set of pages
		* as we don't want these pages allocated for other purposes.
		*/
		start = round_down(phys_initrd_start, PAGE_SIZE);
		size = phys_initrd_size + (phys_initrd_start - start);
		size = round_up(size, PAGE_SIZE);

		if (!memblock_is_region_memory(start, size)) {
		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
		(u64)start, size);
		goto disable;
		}
		if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) {
		pr_err("initrd extends beyond end of memory");

		if (memblock_is_region_reserved(start, size)) {
		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
		(u64)start, size);
		goto disable;
		}

		size = initrd_end - initrd_start;
		memblock_reserve(__pa_symbol(initrd_start), size);
		memblock_reserve(start, size);
		/* Now convert initrd to virtual addresses */
		initrd_start = (unsigned long)__va(phys_initrd_start);
		initrd_end = initrd_start + phys_initrd_size;
		initrd_below_start_ok = 1;

		pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",

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