| Date | Wed, 13 May 2020 19:28:34 -0400 (EDT) | From | Mathieu Desnoyers <> | Subject | Re: [patch V4 part 1 27/36] arm64: Prepare arch_nmi_enter() for recursion |
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----- On May 5, 2020, at 9:16 AM, Thomas Gleixner tglx@linutronix.de wrote:
> +#define arch_nmi_enter() \ [...] \ > + ___hcr = read_sysreg(hcr_el2); \ > + if (!(___hcr & HCR_TGE)) { \ > + write_sysreg(___hcr | HCR_TGE, hcr_el2); \ > + isb(); \
Why is there an isb() above ^ ....
> + } \ > + /* \ [...] > -#define arch_nmi_exit() \ [...] > + /* \ > + * Make sure ___ctx->cnt release is visible before we \ > + * restore the sysreg. Otherwise a new NMI occurring \ > + * right after write_sysreg() can be fooled and think \ > + * we secured things for it. \ > + */ \ > + barrier(); \ > + if (!___ctx->cnt && !(___hcr & HCR_TGE)) \ > + write_sysreg(___hcr, hcr_el2); \
And not here ?
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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