powerpc: Add an inline function to update POWER8 HID0 (e63dbd16) · Commits · 戴 / test

Section 3.7 of Version 1.2 of the Power8 Processor User's Manual prescribes that updates to HID0 be preceded by a SYNC instruction and followed by an ISYNC instruction (Page 91). Create an inline function name update_power8_hid0() which follows this recipe and invoke it from the static split core path. Signed-off-by:

Gautham R. Shenoy <ego@linux.vnet.ibm.com> Reviewed-by:

Sam Bobroff <sam.bobroff@au1.ibm.com> Tested-by:

Sam Bobroff <sam.bobroff@au1.ibm.com> Signed-off-by:

Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/reg.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -1280,6 +1280,15 @@ struct pt_regs;

		extern void ppc_save_regs(struct pt_regs *regs);

		static inline void update_power8_hid0(unsigned long hid0)
		{
		/*
		* The HID0 update on Power8 should at the very least be
		* preceded by a a SYNC instruction followed by an ISYNC
		* instruction
		*/
		asm volatile("sync; mtspr %0,%1; isync":: "i"(SPRN_HID0), "r"(hid0));
		}
		#endif /* __ASSEMBLY__ */
		#endif /* __KERNEL__ */
		#endif /* _ASM_POWERPC_REG_H */

arch/powerpc/platforms/powernv/subcore.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -190,7 +190,7 @@ static void unsplit_core(void)

		hid0 = mfspr(SPRN_HID0);
		hid0 &= ~HID0_POWER8_DYNLPARDIS;
		mtspr(SPRN_HID0, hid0);
		update_power8_hid0(hid0);
		update_hid_in_slw(hid0);

		while (mfspr(SPRN_HID0) & mask)
		@@ -227,7 +227,7 @@ static void split_core(int new_mode)
		/* Write new mode */
		hid0 = mfspr(SPRN_HID0);
		hid0 \|= HID0_POWER8_DYNLPARDIS \| split_parms[i].value;
		mtspr(SPRN_HID0, hid0);
		update_power8_hid0(hid0);
		update_hid_in_slw(hid0);

		/* Wait for it to happen */

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