Merge tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:

 - Add support for (optionally) using queued spinlocks & rwlocks.

 - Support for a new faster system call ABI using the scv instruction on
   Power9 or later.

 - Drop support for the PROT_SAO mmap/mprotect flag as it will be
   unsupported on Power10 and future processors, leaving us with no way
   to implement the functionality it requests. This risks breaking
   userspace, though we believe it is unused in practice.

 - A bug fix for, and then the removal of, our custom stack expansion
   checking. We now allow stack expansion up to the rlimit, like other
   architectures.

 - Remove the remnants of our (previously disabled) topology update
   code, which tried to react to NUMA layout changes on virtualised
   systems, but was prone to crashes and other problems.

 - Add PMU support for Power10 CPUs.

 - A change to our signal trampoline so that we don't unbalance the link
   stack (branch return predictor) in the signal delivery path.

 - Lots of other cleanups, refactorings, smaller features and so on as
   usual.

Thanks to: Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey
Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan
S, Bharata B Rao, Bill Wendling, Bin Meng, Cédric Le Goater, Chris
Packham, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Dan
Williams, David Lamparter, Desnes A. Nunes do Rosario, Erhard F., Finn
Thain, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geoff Levand,
Greg Kurz, Gustavo A. R. Silva, Hari Bathini, Harish, Imre Kaloz, Joel
Stanley, Joe Perches, John Crispin, Jordan Niethe, Kajol Jain, Kamalesh
Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li RongQing, Madhavan
Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal Suchanek, Milton
Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan Chancellor, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver O'Halloran,
Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe Bergheaud,
Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar
Dronamraju, Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza
Cascardo, Thiago Jung Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov,
Wei Yongjun, Wen Xiong, YueHaibing.

* tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (337 commits)
  selftests/powerpc: Fix pkey syscall redefinitions
  powerpc: Fix circular dependency between percpu.h and mmu.h
  powerpc/powernv/sriov: Fix use of uninitialised variable
  selftests/powerpc: Skip vmx/vsx/tar/etc tests on older CPUs
  powerpc/40x: Fix assembler warning about r0
  powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric
  powerpc/papr_scm: Fetch nvdimm performance stats from PHYP
  cpuidle: pseries: Fixup exit latency for CEDE(0)
  cpuidle: pseries: Add function to parse extended CEDE records
  cpuidle: pseries: Set the latency-hint before entering CEDE
  selftests/powerpc: Fix online CPU selection
  powerpc/perf: Consolidate perf_callchain_user_[64|32]()
  powerpc/pseries/hotplug-cpu: Remove double free in error path
  powerpc/pseries/mobility: Add pr_debug() for device tree changes
  powerpc/pseries/mobility: Set pr_fmt()
  powerpc/cacheinfo: Warn if cache object chain becomes unordered
  powerpc/cacheinfo: Improve diagnostics about malformed cache lists
  powerpc/cacheinfo: Use name@unit instead of full DT path in debug messages
  powerpc/cacheinfo: Set pr_fmt()
  powerpc: fix function annotations to avoid section mismatch warnings with gcc-10
  ...

1 files changed, 68 insertions, 43 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 794b754deec23..016bd831908ec 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -471,49 +471,58 @@ EXPORT_SYMBOL(giveup_all);
 
 #ifdef CONFIG_PPC_BOOK3S_64
 #ifdef CONFIG_PPC_FPU
-static int restore_fp(struct task_struct *tsk)
+static bool should_restore_fp(void)
 {
-	if (tsk->thread.load_fp) {
-		load_fp_state(&current->thread.fp_state);
+	if (current->thread.load_fp) {
 		current->thread.load_fp++;
-		return 1;
+		return true;
 	}
-	return 0;
+	return false;
+}
+
+static void do_restore_fp(void)
+{
+	load_fp_state(&current->thread.fp_state);
 }
 #else
-static int restore_fp(struct task_struct *tsk) { return 0; }
+static bool should_restore_fp(void) { return false; }
+static void do_restore_fp(void) { }
 #endif /* CONFIG_PPC_FPU */
 
 #ifdef CONFIG_ALTIVEC
-#define loadvec(thr) ((thr).load_vec)
-static int restore_altivec(struct task_struct *tsk)
+static bool should_restore_altivec(void)
 {
-	if (cpu_has_feature(CPU_FTR_ALTIVEC) && (tsk->thread.load_vec)) {
-		load_vr_state(&tsk->thread.vr_state);
-		tsk->thread.used_vr = 1;
-		tsk->thread.load_vec++;
-
-		return 1;
+	if (cpu_has_feature(CPU_FTR_ALTIVEC) && (current->thread.load_vec)) {
+		current->thread.load_vec++;
+		return true;
 	}
-	return 0;
+	return false;
+}
+
+static void do_restore_altivec(void)
+{
+	load_vr_state(&current->thread.vr_state);
+	current->thread.used_vr = 1;
 }
 #else
-#define loadvec(thr) 0
-static inline int restore_altivec(struct task_struct *tsk) { return 0; }
+static bool should_restore_altivec(void) { return false; }
+static void do_restore_altivec(void) { }
 #endif /* CONFIG_ALTIVEC */
 
 #ifdef CONFIG_VSX
-static int restore_vsx(struct task_struct *tsk)
+static bool should_restore_vsx(void)
 {
-	if (cpu_has_feature(CPU_FTR_VSX)) {
-		tsk->thread.used_vsr = 1;
-		return 1;
-	}
-
-	return 0;
+	if (cpu_has_feature(CPU_FTR_VSX))
+		return true;
+	return false;
+}
+static void do_restore_vsx(void)
+{
+	current->thread.used_vsr = 1;
 }
 #else
-static inline int restore_vsx(struct task_struct *tsk) { return 0; }
+static bool should_restore_vsx(void) { return false; }
+static void do_restore_vsx(void) { }
 #endif /* CONFIG_VSX */
 
 /*
@@ -529,32 +538,42 @@ static inline int restore_vsx(struct task_struct *tsk) { return 0; }
 void notrace restore_math(struct pt_regs *regs)
 {
 	unsigned long msr;
-
-	if (!MSR_TM_ACTIVE(regs->msr) &&
-		!current->thread.load_fp && !loadvec(current->thread))
-		return;
+	unsigned long new_msr = 0;
 
 	msr = regs->msr;
-	msr_check_and_set(msr_all_available);
 
 	/*
-	 * Only reload if the bit is not set in the user MSR, the bit BEING set
-	 * indicates that the registers are hot
+	 * new_msr tracks the facilities that are to be restored. Only reload
+	 * if the bit is not set in the user MSR (if it is set, the registers
+	 * are live for the user thread).
 	 */
-	if ((!(msr & MSR_FP)) && restore_fp(current))
-		msr |= MSR_FP | current->thread.fpexc_mode;
+	if ((!(msr & MSR_FP)) && should_restore_fp())
+		new_msr |= MSR_FP | current->thread.fpexc_mode;
 
-	if ((!(msr & MSR_VEC)) && restore_altivec(current))
-		msr |= MSR_VEC;
+	if ((!(msr & MSR_VEC)) && should_restore_altivec())
+		new_msr |= MSR_VEC;
 
-	if ((msr & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC) &&
-			restore_vsx(current)) {
-		msr |= MSR_VSX;
+	if ((!(msr & MSR_VSX)) && should_restore_vsx()) {
+		if (((msr | new_msr) & (MSR_FP | MSR_VEC)) == (MSR_FP | MSR_VEC))
+			new_msr |= MSR_VSX;
 	}
 
-	msr_check_and_clear(msr_all_available);
+	if (new_msr) {
+		msr_check_and_set(new_msr);
+
+		if (new_msr & MSR_FP)
+			do_restore_fp();
+
+		if (new_msr & MSR_VEC)
+			do_restore_altivec();
+
+		if (new_msr & MSR_VSX)
+			do_restore_vsx();
 
-	regs->msr = msr;
+		msr_check_and_clear(new_msr);
+
+		regs->msr |= new_msr;
+	}
 }
 #endif
 
@@ -1599,6 +1618,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 {
 	struct pt_regs *childregs, *kregs;
 	extern void ret_from_fork(void);
+	extern void ret_from_fork_scv(void);
 	extern void ret_from_kernel_thread(void);
 	void (*f)(void);
 	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
@@ -1635,7 +1655,9 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 		if (usp)
 			childregs->gpr[1] = usp;
 		p->thread.regs = childregs;
-		childregs->gpr[3] = 0;  /* Result from fork() */
+		/* 64s sets this in ret_from_fork */
+		if (!IS_ENABLED(CONFIG_PPC_BOOK3S_64))
+			childregs->gpr[3] = 0;  /* Result from fork() */
 		if (clone_flags & CLONE_SETTLS) {
 			if (!is_32bit_task())
 				childregs->gpr[13] = tls;
@@ -1643,7 +1665,10 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 				childregs->gpr[2] = tls;
 		}
 
-		f = ret_from_fork;
+		if (trap_is_scv(regs))
+			f = ret_from_fork_scv;
+		else
+			f = ret_from_fork;
 	}
 	childregs->msr &= ~(MSR_FP|MSR_VEC|MSR_VSX);
 	sp -= STACK_FRAME_OVERHEAD;