aa9887608e
The NoMMU kernel is broken for QEMU virt machine from Linux-5.9-rc6
because clint_time_val is used even before CLINT driver is probed
at following places:
1. rand_initialize() calls get_cycles() which in-turn uses
clint_time_val
2. boot_init_stack_canary() calls get_cycles() which in-turn
uses clint_time_val
The issue#1 (above) is fixed by providing custom random_get_entropy()
for RISC-V NoMMU kernel. For issue#2 (above), we remove dependency of
boot_init_stack_canary() on get_cycles() and this is aligned with the
boot_init_stack_canary() implementations of ARM, ARM64 and MIPS kernel.
Fixes: d5be89a8d1 ("RISC-V: Resurrect the MMIO timer implementation for M-mode systems")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
30 lines
717 B
C
30 lines
717 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_RISCV_STACKPROTECTOR_H
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#define _ASM_RISCV_STACKPROTECTOR_H
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#include <linux/random.h>
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#include <linux/version.h>
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extern unsigned long __stack_chk_guard;
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/*
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* Initialize the stackprotector canary value.
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*
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* NOTE: this must only be called from functions that never return,
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* and it must always be inlined.
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*/
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static __always_inline void boot_init_stack_canary(void)
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{
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unsigned long canary;
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/* Try to get a semi random initial value. */
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get_random_bytes(&canary, sizeof(canary));
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canary ^= LINUX_VERSION_CODE;
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canary &= CANARY_MASK;
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current->stack_canary = canary;
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__stack_chk_guard = current->stack_canary;
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}
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#endif /* _ASM_RISCV_STACKPROTECTOR_H */
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