s390: fix initrd corruptions with gcov/kcov instrumented kernels
The early C code within arch/s390/kernel/early.c saves ipl parameters before the bss section is cleared. When doing that it jumps to code that is potentially gcov/kcov instrumented. That code in turn will corrupt an initrd that potentially may reside in the not yet ready to be used bss section. Instead of excluding more and more code from gcov/kcov instrumentation provide an early memmove function which will be used to save ipl parameters. The verification if these parameters are actually valid will be done later. Reviewed-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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committed by
Martin Schwidefsky

parent
b5cb9bf8dd
commit
d543a106f9
@@ -392,7 +392,49 @@ static int __init cad_init(void)
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}
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early_initcall(cad_init);
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static __init void rescue_initrd(void)
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static __init void memmove_early(void *dst, const void *src, size_t n)
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{
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unsigned long addr;
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long incr;
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psw_t old;
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if (!n)
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return;
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incr = 1;
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if (dst > src) {
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incr = -incr;
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dst += n - 1;
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src += n - 1;
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}
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old = S390_lowcore.program_new_psw;
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S390_lowcore.program_new_psw.mask = __extract_psw();
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asm volatile(
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" larl %[addr],1f\n"
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" stg %[addr],%[psw_pgm_addr]\n"
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"0: mvc 0(1,%[dst]),0(%[src])\n"
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" agr %[dst],%[incr]\n"
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" agr %[src],%[incr]\n"
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" brctg %[n],0b\n"
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"1:\n"
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: [addr] "=&d" (addr),
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[psw_pgm_addr] "=&Q" (S390_lowcore.program_new_psw.addr),
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[dst] "+&a" (dst), [src] "+&a" (src), [n] "+d" (n)
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: [incr] "d" (incr)
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: "cc", "memory");
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S390_lowcore.program_new_psw = old;
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}
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static __init noinline void ipl_save_parameters(void)
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{
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void *src, *dst;
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src = (void *)(unsigned long) S390_lowcore.ipl_parmblock_ptr;
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dst = (void *) IPL_PARMBLOCK_ORIGIN;
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memmove_early(dst, src, PAGE_SIZE);
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S390_lowcore.ipl_parmblock_ptr = IPL_PARMBLOCK_ORIGIN;
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}
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static __init noinline void rescue_initrd(void)
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{
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#ifdef CONFIG_BLK_DEV_INITRD
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unsigned long min_initrd_addr = (unsigned long) _end + (4UL << 20);
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@@ -406,7 +448,7 @@ static __init void rescue_initrd(void)
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return;
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if (INITRD_START >= min_initrd_addr)
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return;
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memmove((void *) min_initrd_addr, (void *) INITRD_START, INITRD_SIZE);
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memmove_early((void *) min_initrd_addr, (void *) INITRD_START, INITRD_SIZE);
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INITRD_START = min_initrd_addr;
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#endif
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}
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@@ -468,6 +510,7 @@ void __init startup_init(void)
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ipl_save_parameters();
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rescue_initrd();
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clear_bss_section();
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ipl_verify_parameters();
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time_early_init();
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init_kernel_storage_key();
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lockdep_off();
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