RISC-V Fixes for 5.11-rc4

There are a few more fixes than a normal rc4, largely due to the bubble
 introduced by the holiday break:
 
 * A fix to return -ENOSYS for syscall number -1, which previously
   returned an uninitialized value.
 * A fix to time_init() to ensure of_clk_init() has been called, without
   which clock drivers may not be initialized.
 * A fix to the sifive,uart0 driver to properly display the baud rate.  A
   fix to initialize MPIE that allows interrupts to be processed during
   system calls.
 * A fix to avoid erronously begin tracing IRQs when interrupts are
   disabled, which at least triggers suprious lockdep failures.
 * A workaround for a warning related to calling smp_processor_id() while
   preemptible.  The warning itself is suprious on currently availiable
   systems.
 * A fix to properly include the generic time VDSO calls.  A fix to our
   kasan address mapping.  A fix to the HiFive Unleashed device tree,
   which allows the Ethernet PHY to be properly initialized by Linux (as
   opposed to relying on the bootloader).
 * A defconfig update to include SiFive's GPIO driver, which is present
   on the HiFive Unleashed and necessary to initialize the PHY.
 * A fix to avoid allocating memory while initializing reserved memory.
 * A fix to avoid allocating the last 4K of memory, as pointers there
   alias with syscall errors.
 
 There are also two cleanups that should have no functional effect but do
 fix build warnings:
 
 * A cleanup to drop a duplicated definition of PAGE_KERNEL_EXEC.
 * A cleanup to properly declare the asm register SP shim.
 * A cleanup to the rv32 memory size Kconfig entry, to reflect the actual
   size of memory availiable.
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Merge tag 'riscv-for-linus-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:
 "There are a few more fixes than a normal rc4, largely due to the
  bubble introduced by the holiday break:

   - return -ENOSYS for syscall number -1, which previously returned an
     uninitialized value.

   - ensure of_clk_init() has been called in time_init(), without which
     clock drivers may not be initialized.

   - fix sifive,uart0 driver to properly display the baud rate. A fix to
     initialize MPIE that allows interrupts to be processed during
     system calls.

   - avoid erronously begin tracing IRQs when interrupts are disabled,
     which at least triggers suprious lockdep failures.

   - workaround for a warning related to calling smp_processor_id()
     while preemptible. The warning itself is suprious on currently
     availiable systems.

   - properly include the generic time VDSO calls. A fix to our kasan
     address mapping. A fix to the HiFive Unleashed device tree, which
     allows the Ethernet PHY to be properly initialized by Linux (as
     opposed to relying on the bootloader).

   - defconfig update to include SiFive's GPIO driver, which is present
     on the HiFive Unleashed and necessary to initialize the PHY.

   - avoid allocating memory while initializing reserved memory.

   - avoid allocating the last 4K of memory, as pointers there alias
     with syscall errors.

  There are also two cleanups that should have no functional effect but
  do fix build warnings:

   - drop a duplicated definition of PAGE_KERNEL_EXEC.

   - properly declare the asm register SP shim.

   - cleanup the rv32 memory size Kconfig entry, to reflect the actual
     size of memory availiable"

* tag 'riscv-for-linus-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Fix maximum allowed phsyical memory for RV32
  RISC-V: Set current memblock limit
  RISC-V: Do not allocate memblock while iterating reserved memblocks
  riscv: stacktrace: Move register keyword to beginning of declaration
  riscv: defconfig: enable gpio support for HiFive Unleashed
  dts: phy: add GPIO number and active state used for phy reset
  dts: phy: fix missing mdio device and probe failure of vsc8541-01 device
  riscv: Fix KASAN memory mapping.
  riscv: Fixup CONFIG_GENERIC_TIME_VSYSCALL
  riscv: cacheinfo: Fix using smp_processor_id() in preemptible
  riscv: Trace irq on only interrupt is enabled
  riscv: Drop a duplicated PAGE_KERNEL_EXEC
  riscv: Enable interrupts during syscalls with M-Mode
  riscv: Fix sifive serial driver
  riscv: Fix kernel time_init()
  riscv: return -ENOSYS for syscall -1

arch/riscv/Kconfig

@@ -137,7 +137,7 @@ config PA_BITS
 
 config PAGE_OFFSET
 	hex
-	default 0xC0000000 if 32BIT && MAXPHYSMEM_2GB
+	default 0xC0000000 if 32BIT && MAXPHYSMEM_1GB
 	default 0x80000000 if 64BIT && !MMU
 	default 0xffffffff80000000 if 64BIT && MAXPHYSMEM_2GB
 	default 0xffffffe000000000 if 64BIT && MAXPHYSMEM_128GB
@@ -247,10 +247,12 @@ config MODULE_SECTIONS
 
 choice
 	prompt "Maximum Physical Memory"
-	default MAXPHYSMEM_2GB if 32BIT
+	default MAXPHYSMEM_1GB if 32BIT
 	default MAXPHYSMEM_2GB if 64BIT && CMODEL_MEDLOW
 	default MAXPHYSMEM_128GB if 64BIT && CMODEL_MEDANY
 
+	config MAXPHYSMEM_1GB
+		bool "1GiB"
 	config MAXPHYSMEM_2GB
 		bool "2GiB"
 	config MAXPHYSMEM_128GB

arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts

@@ -88,7 +88,9 @@
 	phy-mode = "gmii";
 	phy-handle = <&phy0>;
 	phy0: ethernet-phy@0 {
+		compatible = "ethernet-phy-id0007.0771";
 		reg = <0>;
+		reset-gpios = <&gpio 12 GPIO_ACTIVE_LOW>;
 	};
 };
 

arch/riscv/configs/defconfig

@@ -64,6 +64,8 @@ CONFIG_HW_RANDOM=y
 CONFIG_HW_RANDOM_VIRTIO=y
 CONFIG_SPI=y
 CONFIG_SPI_SIFIVE=y
+CONFIG_GPIOLIB=y
+CONFIG_GPIO_SIFIVE=y
 # CONFIG_PTP_1588_CLOCK is not set
 CONFIG_POWER_RESET=y
 CONFIG_DRM=y

arch/riscv/include/asm/pgtable.h

@@ -99,7 +99,6 @@
 				| _PAGE_DIRTY)
 
 #define PAGE_KERNEL		__pgprot(_PAGE_KERNEL)
-#define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL | _PAGE_EXEC)
 #define PAGE_KERNEL_READ	__pgprot(_PAGE_KERNEL & ~_PAGE_WRITE)
 #define PAGE_KERNEL_EXEC	__pgprot(_PAGE_KERNEL | _PAGE_EXEC)
 #define PAGE_KERNEL_READ_EXEC	__pgprot((_PAGE_KERNEL & ~_PAGE_WRITE) \

arch/riscv/include/asm/vdso.h

@@ -10,7 +10,7 @@
 
 #include <linux/types.h>
 
-#ifndef GENERIC_TIME_VSYSCALL
+#ifndef CONFIG_GENERIC_TIME_VSYSCALL
 struct vdso_data {
 };
 #endif

arch/riscv/kernel/cacheinfo.c

@@ -26,7 +26,16 @@ cache_get_priv_group(struct cacheinfo *this_leaf)
 
 static struct cacheinfo *get_cacheinfo(u32 level, enum cache_type type)
 {
-	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(smp_processor_id());
+	/*
+	 * Using raw_smp_processor_id() elides a preemptability check, but this
+	 * is really indicative of a larger problem: the cacheinfo UABI assumes
+	 * that cores have a homonogenous view of the cache hierarchy.  That
+	 * happens to be the case for the current set of RISC-V systems, but
+	 * likely won't be true in general.  Since there's no way to provide
+	 * correct information for these systems via the current UABI we're
+	 * just eliding the check for now.
+	 */
+	struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(raw_smp_processor_id());
 	struct cacheinfo *this_leaf;
 	int index;
 

arch/riscv/kernel/entry.S

@@ -124,15 +124,15 @@ skip_context_tracking:
 	REG_L a1, (a1)
 	jr a1
 1:
-#ifdef CONFIG_TRACE_IRQFLAGS
-	call trace_hardirqs_on
-#endif
 	/*
 	 * Exceptions run with interrupts enabled or disabled depending on the
 	 * state of SR_PIE in m/sstatus.
 	 */
 	andi t0, s1, SR_PIE
 	beqz t0, 1f
+#ifdef CONFIG_TRACE_IRQFLAGS
+	call trace_hardirqs_on
+#endif
 	csrs CSR_STATUS, SR_IE
 
 1:
@@ -155,6 +155,15 @@ skip_context_tracking:
 	tail do_trap_unknown
 
 handle_syscall:
+#ifdef CONFIG_RISCV_M_MODE
+	/*
+	 * When running is M-Mode (no MMU config), MPIE does not get set.
+	 * As a result, we need to force enable interrupts here because
+	 * handle_exception did not do set SR_IE as it always sees SR_PIE
+	 * being cleared.
+	 */
+	csrs CSR_STATUS, SR_IE
+#endif
 #if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING)
 	/* Recover a0 - a7 for system calls */
 	REG_L a0, PT_A0(sp)
@@ -186,14 +195,7 @@ check_syscall_nr:
 	 * Syscall number held in a7.
 	 * If syscall number is above allowed value, redirect to ni_syscall.
 	 */
-	bge a7, t0, 1f
-	/*
-	 * Check if syscall is rejected by tracer, i.e., a7 == -1.
-	 * If yes, we pretend it was executed.
-	 */
-	li t1, -1
-	beq a7, t1, ret_from_syscall_rejected
-	blt a7, t1, 1f
+	bgeu a7, t0, 1f
 	/* Call syscall */
 	la s0, sys_call_table
 	slli t0, a7, RISCV_LGPTR

arch/riscv/kernel/setup.c

@@ -127,7 +127,9 @@ static void __init init_resources(void)
 {
 	struct memblock_region *region = NULL;
 	struct resource *res = NULL;
-	int ret = 0;
+	struct resource *mem_res = NULL;
+	size_t mem_res_sz = 0;
+	int ret = 0, i = 0;
 
 	code_res.start = __pa_symbol(_text);
 	code_res.end = __pa_symbol(_etext) - 1;
@@ -145,16 +147,17 @@ static void __init init_resources(void)
 	bss_res.end = __pa_symbol(__bss_stop) - 1;
 	bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
 
+	mem_res_sz = (memblock.memory.cnt + memblock.reserved.cnt) * sizeof(*mem_res);
+	mem_res = memblock_alloc(mem_res_sz, SMP_CACHE_BYTES);
+	if (!mem_res)
+		panic("%s: Failed to allocate %zu bytes\n", __func__, mem_res_sz);
 	/*
 	 * Start by adding the reserved regions, if they overlap
 	 * with /memory regions, insert_resource later on will take
 	 * care of it.
 	 */
 	for_each_reserved_mem_region(region) {
-		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
-		if (!res)
-			panic("%s: Failed to allocate %zu bytes\n", __func__,
-			      sizeof(struct resource));
+		res = &mem_res[i++];
 
 		res->name = "Reserved";
 		res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
@@ -171,8 +174,10 @@ static void __init init_resources(void)
 		 * Ignore any other reserved regions within
 		 * system memory.
 		 */
-		if (memblock_is_memory(res->start))
+		if (memblock_is_memory(res->start)) {
+			memblock_free((phys_addr_t) res, sizeof(struct resource));
 			continue;
+		}
 
 		ret = add_resource(&iomem_resource, res);
 		if (ret < 0)
@@ -181,10 +186,7 @@ static void __init init_resources(void)
 
 	/* Add /memory regions to the resource tree */
 	for_each_mem_region(region) {
-		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
-		if (!res)
-			panic("%s: Failed to allocate %zu bytes\n", __func__,
-			      sizeof(struct resource));
+		res = &mem_res[i++];
 
 		if (unlikely(memblock_is_nomap(region))) {
 			res->name = "Reserved";
@@ -205,9 +207,9 @@ static void __init init_resources(void)
 	return;
 
  error:
-	memblock_free((phys_addr_t) res, sizeof(struct resource));
 	/* Better an empty resource tree than an inconsistent one */
 	release_child_resources(&iomem_resource);
+	memblock_free((phys_addr_t) mem_res, mem_res_sz);
 }
 
 

arch/riscv/kernel/stacktrace.c

@@ -14,7 +14,7 @@
 
 #include <asm/stacktrace.h>
 
-register unsigned long sp_in_global __asm__("sp");
+register const unsigned long sp_in_global __asm__("sp");
 
 #ifdef CONFIG_FRAME_POINTER
 
@@ -28,9 +28,8 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
 		sp = user_stack_pointer(regs);
 		pc = instruction_pointer(regs);
 	} else if (task == NULL || task == current) {
-		const register unsigned long current_sp = sp_in_global;
 		fp = (unsigned long)__builtin_frame_address(0);
-		sp = current_sp;
+		sp = sp_in_global;
 		pc = (unsigned long)walk_stackframe;
 	} else {
 		/* task blocked in __switch_to */

arch/riscv/kernel/time.c

@@ -4,6 +4,7 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/of_clk.h>
 #include <linux/clocksource.h>
 #include <linux/delay.h>
 #include <asm/sbi.h>
@@ -24,6 +25,8 @@ void __init time_init(void)
 	riscv_timebase = prop;
 
 	lpj_fine = riscv_timebase / HZ;
+
+	of_clk_init(NULL);
 	timer_probe();
 }
 

arch/riscv/kernel/vdso.c

@@ -12,7 +12,7 @@
 #include <linux/binfmts.h>
 #include <linux/err.h>
 #include <asm/page.h>
-#ifdef GENERIC_TIME_VSYSCALL
+#ifdef CONFIG_GENERIC_TIME_VSYSCALL
 #include <vdso/datapage.h>
 #else
 #include <asm/vdso.h>

arch/riscv/mm/init.c

@@ -157,9 +157,10 @@ disable:
 void __init setup_bootmem(void)
 {
 	phys_addr_t mem_start = 0;
-	phys_addr_t start, end = 0;
+	phys_addr_t start, dram_end, end = 0;
 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
 	phys_addr_t vmlinux_start = __pa_symbol(&_start);
+	phys_addr_t max_mapped_addr = __pa(~(ulong)0);
 	u64 i;
 
 	/* Find the memory region containing the kernel */
@@ -181,7 +182,18 @@ void __init setup_bootmem(void)
 	/* Reserve from the start of the kernel to the end of the kernel */
 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
 
-	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
+	dram_end = memblock_end_of_DRAM();
+
+	/*
+	 * memblock allocator is not aware of the fact that last 4K bytes of
+	 * the addressable memory can not be mapped because of IS_ERR_VALUE
+	 * macro. Make sure that last 4k bytes are not usable by memblock
+	 * if end of dram is equal to maximum addressable memory.
+	 */
+	if (max_mapped_addr == (dram_end - 1))
+		memblock_set_current_limit(max_mapped_addr - 4096);
+
+	max_pfn = PFN_DOWN(dram_end);
 	max_low_pfn = max_pfn;
 	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
 	set_max_mapnr(max_low_pfn);

arch/riscv/mm/kasan_init.c

@@ -93,8 +93,8 @@ void __init kasan_init(void)
 								VMALLOC_END));
 
 	for_each_mem_range(i, &_start, &_end) {
-		void *start = (void *)_start;
-		void *end = (void *)_end;
+		void *start = (void *)__va(_start);
+		void *end = (void *)__va(_end);
 
 		if (start >= end)
 			break;

drivers/tty/serial/sifive.c

@@ -1000,6 +1000,7 @@ static int sifive_serial_probe(struct platform_device *pdev)
 	/* Set up clock divider */
 	ssp->clkin_rate = clk_get_rate(ssp->clk);
 	ssp->baud_rate = SIFIVE_DEFAULT_BAUD_RATE;
+	ssp->port.uartclk = ssp->baud_rate * 16;
 	__ssp_update_div(ssp);
 
 	platform_set_drvdata(pdev, ssp);