powerpc fixes for 5.2 #5

Seven fixes, all for bugs introduced this cycle.
 
 The commit to add KASAN support broke booting on 32-bit SMP machines, due to a
 refactoring that moved some setup out of the secondary CPU path.
 
 A fix for another 32-bit SMP bug introduced by the fast syscall entry
 implementation for 32-bit BOOKE. And a build fix for the same commit.
 
 Our change to allow the DAWR to be force enabled on Power9 introduced a bug in
 KVM, where we clobber r3 leading to a host crash.
 
 The same commit also exposed a previously unreachable bug in the nested KVM
 handling of DAWR, which could lead to an oops in a nested host.
 
 One of the DMA reworks broke the b43legacy WiFi driver on some people's
 powermacs, fix it by enabling a 30-bit ZONE_DMA on 32-bit.
 
 A fix for TLB flushing in KVM introduced a new bug, as it neglected to also
 flush the ERAT, this could lead to memory corruption in the guest.
 
 Thanks to:
   Aaro Koskinen, Christoph Hellwig, Christophe Leroy, Larry Finger, Michael
   Neuling, Suraj Jitindar Singh.
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Merge tag 'powerpc-5.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "This is a frustratingly large batch at rc5. Some of these were sent
  earlier but were missed by me due to being distracted by other things,
  and some took a while to track down due to needing manual bisection on
  old hardware. But still we clearly need to improve our testing of KVM,
  and of 32-bit, so that we catch these earlier.

  Summary: seven fixes, all for bugs introduced this cycle.

   - The commit to add KASAN support broke booting on 32-bit SMP
     machines, due to a refactoring that moved some setup out of the
     secondary CPU path.

   - A fix for another 32-bit SMP bug introduced by the fast syscall
     entry implementation for 32-bit BOOKE. And a build fix for the same
     commit.

   - Our change to allow the DAWR to be force enabled on Power9
     introduced a bug in KVM, where we clobber r3 leading to a host
     crash.

   - The same commit also exposed a previously unreachable bug in the
     nested KVM handling of DAWR, which could lead to an oops in a
     nested host.

   - One of the DMA reworks broke the b43legacy WiFi driver on some
     people's powermacs, fix it by enabling a 30-bit ZONE_DMA on 32-bit.

   - A fix for TLB flushing in KVM introduced a new bug, as it neglected
     to also flush the ERAT, this could lead to memory corruption in the
     guest.

  Thanks to: Aaro Koskinen, Christoph Hellwig, Christophe Leroy, Larry
  Finger, Michael Neuling, Suraj Jitindar Singh"

* tag 'powerpc-5.2-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  KVM: PPC: Book3S HV: Invalidate ERAT when flushing guest TLB entries
  powerpc: enable a 30-bit ZONE_DMA for 32-bit pmac
  KVM: PPC: Book3S HV: Only write DAWR[X] when handling h_set_dawr in real mode
  KVM: PPC: Book3S HV: Fix r3 corruption in h_set_dabr()
  powerpc/32: fix build failure on book3e with KVM
  powerpc/booke: fix fast syscall entry on SMP
  powerpc/32s: fix initial setup of segment registers on secondary CPU

arch/powerpc/include/asm/page.h

@@ -319,6 +319,13 @@ struct vm_area_struct;
 #endif /* __ASSEMBLY__ */
 #include <asm/slice.h>
 
+/*
+ * Allow 30-bit DMA for very limited Broadcom wifi chips on many powerbooks.
+ */
+#ifdef CONFIG_PPC32
+#define ARCH_ZONE_DMA_BITS 30
+#else
 #define ARCH_ZONE_DMA_BITS 31
+#endif
 
 #endif /* _ASM_POWERPC_PAGE_H */

arch/powerpc/kernel/head_32.S

@@ -752,6 +752,7 @@ __secondary_start:
 	stw	r0,0(r3)
 
 	/* load up the MMU */
+	bl	load_segment_registers
 	bl	load_up_mmu
 
 	/* ptr to phys current thread */

arch/powerpc/kernel/head_booke.h

@@ -83,7 +83,7 @@ END_BTB_FLUSH_SECTION
 	SAVE_4GPRS(3, r11);						     \
 	SAVE_2GPRS(7, r11)
 
-.macro SYSCALL_ENTRY trapno intno
+.macro SYSCALL_ENTRY trapno intno srr1
 	mfspr	r10, SPRN_SPRG_THREAD
 #ifdef CONFIG_KVM_BOOKE_HV
 BEGIN_FTR_SECTION
@@ -94,7 +94,7 @@ BEGIN_FTR_SECTION
 	mfspr	r11, SPRN_SRR1
 	mtocrf	0x80, r11	/* check MSR[GS] without clobbering reg */
 	bf	3, 1975f
-	b	kvmppc_handler_BOOKE_INTERRUPT_\intno\()_SPRN_SRR1
+	b	kvmppc_handler_\intno\()_\srr1
 1975:
 	mr	r12, r13
 	lwz	r13, THREAD_NORMSAVE(2)(r10)
@@ -145,9 +145,9 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	tophys(r11,r11)
 	addi	r11,r11,global_dbcr0@l
 #ifdef CONFIG_SMP
-	lwz	r9,TASK_CPU(r2)
-	slwi	r9,r9,3
-	add	r11,r11,r9
+	lwz	r10, TASK_CPU(r2)
+	slwi	r10, r10, 3
+	add	r11, r11, r10
 #endif
 	lwz	r12,0(r11)
 	mtspr	SPRN_DBCR0,r12

arch/powerpc/kernel/head_fsl_booke.S

@@ -409,7 +409,7 @@ interrupt_base:
 
 	/* System Call Interrupt */
 	START_EXCEPTION(SystemCall)
-	SYSCALL_ENTRY   0xc00 SYSCALL
+	SYSCALL_ENTRY   0xc00 BOOKE_INTERRUPT_SYSCALL SPRN_SRR1
 
 	/* Auxiliary Processor Unavailable Interrupt */
 	EXCEPTION(0x2900, AP_UNAVAIL, AuxillaryProcessorUnavailable, \

arch/powerpc/kvm/book3s_hv_builtin.c

@@ -830,6 +830,7 @@ static void flush_guest_tlb(struct kvm *kvm)
 		}
 	}
 	asm volatile("ptesync": : :"memory");
+	asm volatile(PPC_INVALIDATE_ERAT : : :"memory");
 }
 
 void kvmppc_check_need_tlb_flush(struct kvm *kvm, int pcpu,

arch/powerpc/kvm/book3s_hv_rmhandlers.S

@@ -2500,17 +2500,28 @@ END_FTR_SECTION_IFSET(CPU_FTR_ARCH_207S)
 	LOAD_REG_ADDR(r11, dawr_force_enable)
 	lbz	r11, 0(r11)
 	cmpdi	r11, 0
+	bne	3f
 	li	r3, H_HARDWARE
-	beqlr
+	blr
+3:
 	/* Emulate H_SET_DABR/X on P8 for the sake of compat mode guests */
 	rlwimi	r5, r4, 5, DAWRX_DR | DAWRX_DW
 	rlwimi	r5, r4, 2, DAWRX_WT
 	clrrdi	r4, r4, 3
 	std	r4, VCPU_DAWR(r3)
 	std	r5, VCPU_DAWRX(r3)
+	/*
+	 * If came in through the real mode hcall handler then it is necessary
+	 * to write the registers since the return path won't. Otherwise it is
+	 * sufficient to store then in the vcpu struct as they will be loaded
+	 * next time the vcpu is run.
+	 */
+	mfmsr	r6
+	andi.	r6, r6, MSR_DR		/* in real mode? */
+	bne	4f
 	mtspr	SPRN_DAWR, r4
 	mtspr	SPRN_DAWRX, r5
-	li	r3, 0
+4:	li	r3, 0
 	blr
 
 _GLOBAL(kvmppc_h_cede)		/* r3 = vcpu pointer, r11 = msr, r13 = paca */

arch/powerpc/mm/mem.c

@@ -248,7 +248,8 @@ void __init paging_init(void)
 	       (long int)((top_of_ram - total_ram) >> 20));
 
 #ifdef CONFIG_ZONE_DMA
-	max_zone_pfns[ZONE_DMA]	= min(max_low_pfn, 0x7fffffffUL >> PAGE_SHIFT);
+	max_zone_pfns[ZONE_DMA]	= min(max_low_pfn,
+			((1UL << ARCH_ZONE_DMA_BITS) - 1) >> PAGE_SHIFT);
 #endif
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 #ifdef CONFIG_HIGHMEM

arch/powerpc/platforms/powermac/Kconfig

@@ -7,6 +7,7 @@ config PPC_PMAC
 	select PPC_INDIRECT_PCI if PPC32
 	select PPC_MPC106 if PPC32
 	select PPC_NATIVE
+	select ZONE_DMA if PPC32
 	default y
 
 config PPC_PMAC64