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Commit 2a8870f5 authored by Hari Bathini's avatar Hari Bathini Committed by Greg Kroah-Hartman
Browse files

powerpc: handle kdump appropriately with crash_kexec_post_notifiers option 



[ Upstream commit 219572d2fc4135b5ce65c735d881787d48b10e71 ]

Kdump can be triggered after panic_notifers since commit f06e5153
("kernel/panic.c: add "crash_kexec_post_notifiers" option for kdump
after panic_notifers") introduced crash_kexec_post_notifiers option.
But using this option would mean smp_send_stop(), that marks all other
CPUs as offline, gets called before kdump is triggered. As a result,
kdump routines fail to save other CPUs' registers. To fix this, kdump
friendly crash_smp_send_stop() function was introduced with kernel
commit 0ee59413 ("x86/panic: replace smp_send_stop() with kdump
friendly version in panic path"). Override this kdump friendly weak
function to handle crash_kexec_post_notifiers option appropriately
on powerpc.

Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarHari Bathini <hbathini@linux.ibm.com>
[Fixed signature of crash_stop_this_cpu() - reported by lkp@intel.com]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211207103719.91117-1-hbathini@linux.ibm.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 2dbb618e

arch/powerpc/kernel/smp.c

+30 −0
Original line number Diff line number Diff line
@@ -582,6 +582,36 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *)) 
}

#endif



#ifdef CONFIG_NMI_IPI

static void crash_stop_this_cpu(struct pt_regs *regs)

#else

static void crash_stop_this_cpu(void *dummy)

#endif

{

	/*

	 * Just busy wait here and avoid marking CPU as offline to ensure

	 * register data is captured appropriately.

	 */

	while (1)

		cpu_relax();

}



void crash_smp_send_stop(void)

{

	static bool stopped = false;



	if (stopped)

		return;



	stopped = true;



#ifdef CONFIG_NMI_IPI

	smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, crash_stop_this_cpu, 1000000);

#else

	smp_call_function(crash_stop_this_cpu, NULL, 0);

#endif /* CONFIG_NMI_IPI */

}



#ifdef CONFIG_NMI_IPI

static void nmi_stop_this_cpu(struct pt_regs *regs)

{