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Commit 54820530 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

powerpc/powernv: Enable TM without suspend if possible 



Some Power9 revisions can run in a mode where TM operates without
suspended state. If we find ourself on a CPU that might be in this
mode, we query OPAL to check, and if so we reenable TM in CPU
features, and enable a new user feature to signal to userspace that we
are in this mode.

We do not enable the "normal" user feature, PPC_FEATURE2_HTM, but we
do enable PPC_FEATURE2_HTM_NOSC because that indicates to userspace
that the kernel will abort transactions on syscall entry, which is
true regardless of the suspend mode.

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent cba6ac48

arch/powerpc/include/asm/opal-api.h

+2 −0
Original line number Diff line number Diff line
@@ -896,6 +896,8 @@ enum { 
	 */

	OPAL_REINIT_CPUS_MMU_HASH	= (1 << 2),

	OPAL_REINIT_CPUS_MMU_RADIX	= (1 << 3),



	OPAL_REINIT_CPUS_TM_SUSPEND_DISABLED = (1 << 4),

};



typedef struct oppanel_line {

arch/powerpc/include/asm/powernv.h

+4 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ extern void pnv_npu2_destroy_context(struct npu_context *context, 
extern int pnv_npu2_handle_fault(struct npu_context *context, uintptr_t *ea,

				unsigned long *flags, unsigned long *status,

				int count);



void pnv_tm_init(void);

#else

static inline void powernv_set_nmmu_ptcr(unsigned long ptcr) { }

static inline struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
@@ -36,6 +38,8 @@ static inline int pnv_npu2_handle_fault(struct npu_context *context, 
					unsigned long *status, int count) {

	return -ENODEV;

}



static inline void pnv_tm_init(void) { }

#endif



#endif /* _ASM_POWERNV_H */

arch/powerpc/include/asm/tm.h

+2 −0
Original line number Diff line number Diff line
@@ -19,4 +19,6 @@ extern void tm_abort(uint8_t cause); 
extern void tm_save_sprs(struct thread_struct *thread);

extern void tm_restore_sprs(struct thread_struct *thread);



extern bool tm_suspend_disabled;



#endif /* __ASSEMBLY__ */

arch/powerpc/kernel/process.c

+7 −0
Original line number Diff line number Diff line
@@ -77,6 +77,13 @@ 
extern unsigned long _get_SP(void);



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM

/*

 * Are we running in "Suspend disabled" mode? If so we have to block any

 * sigreturn that would get us into suspended state, and we also warn in some

 * other paths that we should never reach with suspend disabled.

 */

bool tm_suspend_disabled __ro_after_init = false;



static void check_if_tm_restore_required(struct task_struct *tsk)

{

	/*

arch/powerpc/kernel/prom.c

+4 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <asm/mmu.h>

#include <asm/paca.h>

#include <asm/pgtable.h>

#include <asm/powernv.h>

#include <asm/iommu.h>

#include <asm/btext.h>

#include <asm/sections.h>
@@ -681,7 +682,10 @@ static void __init tm_init(void) 
		cur_cpu_spec->cpu_user_features2 &=

			~(PPC_FEATURE2_HTM_NOSC | PPC_FEATURE2_HTM);

		cur_cpu_spec->cpu_features &= ~CPU_FTR_TM;

		return;

	}



	pnv_tm_init();

}

#else

static void tm_init(void) { }