powerpc fixes for 5.19 #3

- A fix for a CMA change that broke booting guests with > 2G RAM on Power8 hosts.
 
  - Fix the RTAS call filter to allow a special case that applications rely on.
 
  - A change to our execve path, to make the execve syscall exit tracepoint work.
 
  - Three fixes to wire up our various RNGs earlier in boot so they're available for use in
    the initial seeding in random_init().
 
  - A build fix for when KASAN is enabled along with STRUCTLEAK_BYREF_ALL.
 
 Thanks to: Andrew Donnellan, Aneesh Kumar K.V, Christophe Leroy, Jason A. Donenfeld,
 Nathan Lynch, Naveen N. Rao, Sathvika Vasireddy, Sumit Dubey2, Tyrel Datwyler, Zi Yan.
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Merge tag 'powerpc-5.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - A fix for a CMA change that broke booting guests with > 2G RAM on
   Power8 hosts.

 - Fix the RTAS call filter to allow a special case that applications
   rely on.

 - A change to our execve path, to make the execve syscall exit
   tracepoint work.

 - Three fixes to wire up our various RNGs earlier in boot so they're
   available for use in the initial seeding in random_init().

 - A build fix for when KASAN is enabled along with
   STRUCTLEAK_BYREF_ALL.

Thanks to Andrew Donnellan, Aneesh Kumar K.V, Christophe Leroy, Jason
Donenfeld, Nathan Lynch, Naveen N. Rao, Sathvika Vasireddy, Sumit
Dubey2, Tyrel Datwyler, and Zi Yan.

* tag 'powerpc-5.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv: wire up rng during setup_arch
  powerpc/prom_init: Fix build failure with GCC_PLUGIN_STRUCTLEAK_BYREF_ALL and KASAN
  powerpc/rtas: Allow ibm,platform-dump RTAS call with null buffer address
  powerpc: Enable execve syscall exit tracepoint
  powerpc/pseries: wire up rng during setup_arch()
  powerpc/microwatt: wire up rng during setup_arch()
  powerpc/mm: Move CMA reservations after initmem_init()

arch/powerpc/kernel/process.c

@@ -1855,7 +1855,7 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 		tm_reclaim_current(0);
 #endif
 
-	memset(regs->gpr, 0, sizeof(regs->gpr));
+	memset(&regs->gpr[1], 0, sizeof(regs->gpr) - sizeof(regs->gpr[0]));
 	regs->ctr = 0;
 	regs->link = 0;
 	regs->xer = 0;

arch/powerpc/kernel/prom_init.c

@@ -2302,7 +2302,7 @@ static void __init prom_init_stdout(void)
 
 static int __init prom_find_machine_type(void)
 {
-	char compat[256];
+	static char compat[256] __prombss;
 	int len, i = 0;
 #ifdef CONFIG_PPC64
 	phandle rtas;

arch/powerpc/kernel/rtas.c

@@ -1071,7 +1071,7 @@ static struct rtas_filter rtas_filters[] __ro_after_init = {
 	{ "get-time-of-day", -1, -1, -1, -1, -1 },
 	{ "ibm,get-vpd", -1, 0, -1, 1, 2 },
 	{ "ibm,lpar-perftools", -1, 2, 3, -1, -1 },
-	{ "ibm,platform-dump", -1, 4, 5, -1, -1 },
+	{ "ibm,platform-dump", -1, 4, 5, -1, -1 },		/* Special cased */
 	{ "ibm,read-slot-reset-state", -1, -1, -1, -1, -1 },
 	{ "ibm,scan-log-dump", -1, 0, 1, -1, -1 },
 	{ "ibm,set-dynamic-indicator", -1, 2, -1, -1, -1 },
@@ -1120,6 +1120,15 @@ static bool block_rtas_call(int token, int nargs,
 				size = 1;
 
 			end = base + size - 1;
+
+			/*
+			 * Special case for ibm,platform-dump - NULL buffer
+			 * address is used to indicate end of dump processing
+			 */
+			if (!strcmp(f->name, "ibm,platform-dump") &&
+			    base == 0)
+				return false;
+
 			if (!in_rmo_buf(base, end))
 				goto err;
 		}

arch/powerpc/kernel/setup-common.c

@@ -935,12 +935,6 @@ void __init setup_arch(char **cmdline_p)
 	/* Print various info about the machine that has been gathered so far. */
 	print_system_info();
 
-	/* Reserve large chunks of memory for use by CMA for KVM. */
-	kvm_cma_reserve();
-
-	/*  Reserve large chunks of memory for us by CMA for hugetlb */
-	gigantic_hugetlb_cma_reserve();
-
 	klp_init_thread_info(&init_task);
 
 	setup_initial_init_mm(_stext, _etext, _edata, _end);
@@ -955,6 +949,13 @@ void __init setup_arch(char **cmdline_p)
 
 	initmem_init();
 
+	/*
+	 * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must
+	 * be called after initmem_init(), so that pageblock_order is initialised.
+	 */
+	kvm_cma_reserve();
+	gigantic_hugetlb_cma_reserve();
+
 	early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT);
 
 	if (ppc_md.setup_arch)

arch/powerpc/platforms/microwatt/microwatt.h

@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _MICROWATT_H
+#define _MICROWATT_H
+
+void microwatt_rng_init(void);
+
+#endif /* _MICROWATT_H */

arch/powerpc/platforms/microwatt/rng.c

@@ -11,6 +11,7 @@
 #include <asm/archrandom.h>
 #include <asm/cputable.h>
 #include <asm/machdep.h>
+#include "microwatt.h"
 
 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul
 
@@ -29,7 +30,7 @@ static int microwatt_get_random_darn(unsigned long *v)
 	return 1;
 }
 
-static __init int rng_init(void)
+void __init microwatt_rng_init(void)
 {
 	unsigned long val;
 	int i;
@@ -37,12 +38,7 @@ static __init int rng_init(void)
 	for (i = 0; i < 10; i++) {
 		if (microwatt_get_random_darn(&val)) {
 			ppc_md.get_random_seed = microwatt_get_random_darn;
-			return 0;
+			return;
 		}
 	}
-
-	pr_warn("Unable to use DARN for get_random_seed()\n");
-
-	return -EIO;
 }
-machine_subsys_initcall(, rng_init);

arch/powerpc/platforms/microwatt/setup.c

@@ -16,6 +16,8 @@
 #include <asm/xics.h>
 #include <asm/udbg.h>
 
+#include "microwatt.h"
+
 static void __init microwatt_init_IRQ(void)
 {
 	xics_init();
@@ -32,10 +34,16 @@ static int __init microwatt_populate(void)
 }
 machine_arch_initcall(microwatt, microwatt_populate);
 
+static void __init microwatt_setup_arch(void)
+{
+	microwatt_rng_init();
+}
+
 define_machine(microwatt) {
 	.name			= "microwatt",
 	.probe			= microwatt_probe,
 	.init_IRQ		= microwatt_init_IRQ,
+	.setup_arch		= microwatt_setup_arch,
 	.progress		= udbg_progress,
 	.calibrate_decr		= generic_calibrate_decr,
 };

arch/powerpc/platforms/powernv/powernv.h

@@ -42,4 +42,6 @@ ssize_t memcons_copy(struct memcons *mc, char *to, loff_t pos, size_t count);
 u32 __init memcons_get_size(struct memcons *mc);
 struct memcons *__init memcons_init(struct device_node *node, const char *mc_prop_name);
 
+void pnv_rng_init(void);
+
 #endif /* _POWERNV_H */

arch/powerpc/platforms/powernv/rng.c

@@ -17,6 +17,7 @@
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/smp.h>
+#include "powernv.h"
 
 #define DARN_ERR 0xFFFFFFFFFFFFFFFFul
 
@@ -28,7 +29,6 @@ struct powernv_rng {
 
 static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
 
-
 int powernv_hwrng_present(void)
 {
 	struct powernv_rng *rng;
@@ -98,9 +98,6 @@ static int __init initialise_darn(void)
 			return 0;
 		}
 	}
-
-	pr_warn("Unable to use DARN for get_random_seed()\n");
-
 	return -EIO;
 }
 
@@ -163,32 +160,55 @@ static __init int rng_create(struct device_node *dn)
 
 	rng_init_per_cpu(rng, dn);
 
-	pr_info_once("Registering arch random hook.\n");
-
 	ppc_md.get_random_seed = powernv_get_random_long;
 
 	return 0;
 }
 
-static __init int rng_init(void)
+static int __init pnv_get_random_long_early(unsigned long *v)
 {
 	struct device_node *dn;
-	int rc;
+
+	if (!slab_is_available())
+		return 0;
+
+	if (cmpxchg(&ppc_md.get_random_seed, pnv_get_random_long_early,
+		    NULL) != pnv_get_random_long_early)
+		return 0;
 
 	for_each_compatible_node(dn, NULL, "ibm,power-rng") {
-		rc = rng_create(dn);
-		if (rc) {
-			pr_err("Failed creating rng for %pOF (%d).\n",
-				dn, rc);
+		if (rng_create(dn))
 			continue;
-		}
-
 		/* Create devices for hwrng driver */
 		of_platform_device_create(dn, NULL, NULL);
 	}
 
-	initialise_darn();
+	if (!ppc_md.get_random_seed)
+		return 0;
+	return ppc_md.get_random_seed(v);
+}
 
+void __init pnv_rng_init(void)
+{
+	struct device_node *dn;
+
+	/* Prefer darn over the rest. */
+	if (!initialise_darn())
+		return;
+
+	dn = of_find_compatible_node(NULL, NULL, "ibm,power-rng");
+	if (dn)
+		ppc_md.get_random_seed = pnv_get_random_long_early;
+
+	of_node_put(dn);
+}
+
+static int __init pnv_rng_late_init(void)
+{
+	unsigned long v;
+	/* In case it wasn't called during init for some other reason. */
+	if (ppc_md.get_random_seed == pnv_get_random_long_early)
+		pnv_get_random_long_early(&v);
 	return 0;
 }
-machine_subsys_initcall(powernv, rng_init);
+machine_subsys_initcall(powernv, pnv_rng_late_init);

arch/powerpc/platforms/powernv/setup.c

@@ -203,6 +203,8 @@ static void __init pnv_setup_arch(void)
 	pnv_check_guarded_cores();
 
 	/* XXX PMCS */
+
+	pnv_rng_init();
 }
 
 static void __init pnv_init(void)

arch/powerpc/platforms/pseries/pseries.h

@@ -122,4 +122,6 @@ void pseries_lpar_read_hblkrm_characteristics(void);
 static inline void pseries_lpar_read_hblkrm_characteristics(void) { }
 #endif
 
+void pseries_rng_init(void);
+
 #endif /* _PSERIES_PSERIES_H */

arch/powerpc/platforms/pseries/rng.c

@@ -10,6 +10,7 @@
 #include <asm/archrandom.h>
 #include <asm/machdep.h>
 #include <asm/plpar_wrappers.h>
+#include "pseries.h"
 
 
 static int pseries_get_random_long(unsigned long *v)
@@ -24,19 +25,13 @@ static int pseries_get_random_long(unsigned long *v)
 	return 0;
 }
 
-static __init int rng_init(void)
+void __init pseries_rng_init(void)
 {
 	struct device_node *dn;
 
 	dn = of_find_compatible_node(NULL, NULL, "ibm,random");
 	if (!dn)
-		return -ENODEV;
-
-	pr_info("Registering arch random hook.\n");
-
+		return;
 	ppc_md.get_random_seed = pseries_get_random_long;
-
 	of_node_put(dn);
-	return 0;
 }
-machine_subsys_initcall(pseries, rng_init);

arch/powerpc/platforms/pseries/setup.c

@@ -839,6 +839,7 @@ static void __init pSeries_setup_arch(void)
 	}
 
 	ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
+	pseries_rng_init();
 }
 
 static void pseries_panic(char *str)