8e365396d4
Current version of qemu raise an exception when accessing invalid memory. Modify the probing code to temporary redirect the exception handler like on ARM platform. Also move saving of the stack frame out to trap_util.S to have all at the same place for a future rewrite. TEST=boots to ramstage Change-Id: I25860f688c7546714f6fdbce8c8f96da6400813c Signed-off-by: Philipp Hug <philipp@hug.cx> Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/c/coreboot/+/36486 Reviewed-by: ron minnich <rminnich@gmail.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#include <types.h>
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#include <symbols.h>
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#include <device/mmio.h>
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#include <ramdetect.h>
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#include <console/console.h>
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#define OVERLAP(a, b, s, e) ((b) > (s) && (a) < (e))
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int __weak probe_mb(const uintptr_t dram_start, const uintptr_t size)
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{
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uintptr_t addr = dram_start + (size * MiB) - sizeof(uint32_t);
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static const uint32_t patterns[] = {0x55aa55aa, 0x12345678};
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void *ptr = (void *)addr;
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size_t i;
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/* Don't accidentally clobber oneself. */
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if (OVERLAP(addr, addr + sizeof(uint32_t), (uintptr_t)_program, (uintptr_t)_eprogram))
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return 1;
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uint32_t old = read32(ptr);
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for (i = 0; i < ARRAY_SIZE(patterns); i++) {
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write32(ptr, patterns[i]);
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if (read32(ptr) != patterns[i])
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break;
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}
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write32(ptr, old);
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return i == ARRAY_SIZE(patterns);
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}
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/* - 20 as probe_size is in MiB, - 1 as i is signed */
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#define MAX_ADDRESSABLE_SPACE (sizeof(size_t) * 8 - 20 - 1)
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/* Probe an area if it's read/writable. */
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size_t probe_ramsize(const uintptr_t dram_start, const size_t probe_size)
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{
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ssize_t i;
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size_t msb = 0;
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size_t discovered = 0;
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static size_t saved_result;
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if (saved_result)
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return saved_result;
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/* Find the MSB + 1. */
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size_t tmp = probe_size;
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do {
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msb++;
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} while (tmp >>= 1);
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/* Limit search to accessible address space */
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msb = MIN(msb, MAX_ADDRESSABLE_SPACE);
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/* Compact binary search. */
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for (i = msb; i >= 0; i--) {
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if ((discovered | (1ULL << i)) > probe_size)
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continue;
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if (probe_mb(dram_start, (discovered | (1ULL << i))))
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discovered |= (1ULL << i);
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}
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saved_result = discovered;
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printk(BIOS_DEBUG, "RAMDETECT: Found %zu MiB RAM\n", discovered);
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return discovered;
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}
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