RISC-V Fixes for 6.4-rc5

* A build warning fix for BUILTIN_DTB=y.
 * Hibernation support is hidden behind NONPORTABLE, as it depends on
   some undocumented early boot behavior and breaks on most platforms.
 * A fix for relocatable kernels on systems with early boot errata.
 * A fix to properly handle perf callchains for kernel tracepoints.
 * A pair of fixes for NAPOT to avoid inconsistencies between PTEs and
   handle hardware that sets arbitrary A/D bits.
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Merge tag 'riscv-for-linus-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fixes from Palmer Dabbelt:

 - A build warning fix for BUILTIN_DTB=y

 - Hibernation support is hidden behind NONPORTABLE, as it depends on
   some undocumented early boot behavior and breaks on most platforms

 - A fix for relocatable kernels on systems with early boot errata

 - A fix to properly handle perf callchains for kernel tracepoints

 - A pair of fixes for NAPOT to avoid inconsistencies between PTEs and
   handle hardware that sets arbitrary A/D bits

* tag 'riscv-for-linus-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Implement missing huge_ptep_get
  riscv: Fix huge_ptep_set_wrprotect when PTE is a NAPOT
  riscv: perf: Fix callchain parse error with kernel tracepoint events
  riscv: Fix relocatable kernels with early alternatives using -fno-pie
  RISC-V: mark hibernation as nonportable
  riscv: Fix unused variable warning when BUILTIN_DTB is set

arch/riscv/Kconfig

@@ -799,8 +799,11 @@ menu "Power management options"
 
 source "kernel/power/Kconfig"
 
+# Hibernation is only possible on systems where the SBI implementation has
+# marked its reserved memory as not accessible from, or does not run
+# from the same memory as, Linux
 config ARCH_HIBERNATION_POSSIBLE
-	def_bool y
+	def_bool NONPORTABLE
 
 config ARCH_HIBERNATION_HEADER
 	def_bool HIBERNATION

arch/riscv/errata/Makefile

@@ -1,2 +1,6 @@
+ifdef CONFIG_RELOCATABLE
+KBUILD_CFLAGS += -fno-pie
+endif
+
 obj-$(CONFIG_ERRATA_SIFIVE) += sifive/
 obj-$(CONFIG_ERRATA_THEAD) += thead/

arch/riscv/include/asm/hugetlb.h

@@ -36,6 +36,9 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr, pte_t *ptep,
 			       pte_t pte, int dirty);
 
+#define __HAVE_ARCH_HUGE_PTEP_GET
+pte_t huge_ptep_get(pte_t *ptep);
+
 pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags);
 #define arch_make_huge_pte arch_make_huge_pte
 

arch/riscv/include/asm/perf_event.h

@@ -10,4 +10,11 @@
 
 #include <linux/perf_event.h>
 #define perf_arch_bpf_user_pt_regs(regs) (struct user_regs_struct *)regs
+
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+	(regs)->epc = (__ip); \
+	(regs)->s0 = (unsigned long) __builtin_frame_address(0); \
+	(regs)->sp = current_stack_pointer; \
+	(regs)->status = SR_PP; \
+}
 #endif /* _ASM_RISCV_PERF_EVENT_H */

arch/riscv/kernel/Makefile

@@ -23,6 +23,10 @@ ifdef CONFIG_FTRACE
 CFLAGS_REMOVE_alternative.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_cpufeature.o = $(CC_FLAGS_FTRACE)
 endif
+ifdef CONFIG_RELOCATABLE
+CFLAGS_alternative.o += -fno-pie
+CFLAGS_cpufeature.o += -fno-pie
+endif
 ifdef CONFIG_KASAN
 KASAN_SANITIZE_alternative.o := n
 KASAN_SANITIZE_cpufeature.o := n

arch/riscv/mm/hugetlbpage.c

@@ -3,6 +3,30 @@
 #include <linux/err.h>
 
 #ifdef CONFIG_RISCV_ISA_SVNAPOT
+pte_t huge_ptep_get(pte_t *ptep)
+{
+	unsigned long pte_num;
+	int i;
+	pte_t orig_pte = ptep_get(ptep);
+
+	if (!pte_present(orig_pte) || !pte_napot(orig_pte))
+		return orig_pte;
+
+	pte_num = napot_pte_num(napot_cont_order(orig_pte));
+
+	for (i = 0; i < pte_num; i++, ptep++) {
+		pte_t pte = ptep_get(ptep);
+
+		if (pte_dirty(pte))
+			orig_pte = pte_mkdirty(orig_pte);
+
+		if (pte_young(pte))
+			orig_pte = pte_mkyoung(orig_pte);
+	}
+
+	return orig_pte;
+}
+
 pte_t *huge_pte_alloc(struct mm_struct *mm,
 		      struct vm_area_struct *vma,
 		      unsigned long addr,
@@ -218,6 +242,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
 {
 	pte_t pte = ptep_get(ptep);
 	unsigned long order;
+	pte_t orig_pte;
 	int i, pte_num;
 
 	if (!pte_napot(pte)) {
@@ -228,9 +253,12 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
 	order = napot_cont_order(pte);
 	pte_num = napot_pte_num(order);
 	ptep = huge_pte_offset(mm, addr, napot_cont_size(order));
+	orig_pte = get_clear_contig_flush(mm, addr, ptep, pte_num);
+
+	orig_pte = pte_wrprotect(orig_pte);
 
 	for (i = 0; i < pte_num; i++, addr += PAGE_SIZE, ptep++)
-		ptep_set_wrprotect(mm, addr, ptep);
+		set_pte_at(mm, addr, ptep, orig_pte);
 }
 
 pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,

arch/riscv/mm/init.c

@@ -922,9 +922,9 @@ static void __init create_kernel_page_table(pgd_t *pgdir, bool early)
 static void __init create_fdt_early_page_table(uintptr_t fix_fdt_va,
 					       uintptr_t dtb_pa)
 {
+#ifndef CONFIG_BUILTIN_DTB
 	uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);
 
-#ifndef CONFIG_BUILTIN_DTB
 	/* Make sure the fdt fixmap address is always aligned on PMD size */
 	BUILD_BUG_ON(FIX_FDT % (PMD_SIZE / PAGE_SIZE));