[Qemu-devel] [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE

[Qemu-devel] [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

This series includes support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE. This requires
extracting MIPS.abiflags section from ELF file and fp_abi value handling.

v1->v2:

  - added commit messages
  - fixed exit() error codes and appropriate exit messages printed
  - minor code alignments

Stefan Markovic (6):
  Define MIPS_ABI_FP_UNKNOWN macro
  Extend image_info struct with MIPS specific fp_abi and    
    interp_fp_abi fields
  Extract MIPS abiflags from ELF file
  Read and set FP ABI value from MIPS abiflags
  Determine the desired FPU mode
  Add prctl() PR_SET_FP_MODE and PR_GET_FP_MODE implementations

 include/elf.h                      |  2 +
 linux-user/elfload.c               | 37 +++++++++++++++++++
 linux-user/mips/cpu_loop.c         | 75 ++++++++++++++++++++++++++++++++++++++
 linux-user/mips/target_syscall.h   |  2 +
 linux-user/mips64/target_syscall.h |  2 +
 linux-user/qemu.h                  |  4 ++
 linux-user/syscall.c               | 62 +++++++++++++++++++++++++++++--
 7 files changed, 180 insertions(+), 4 deletions(-)

-- 
1.9.1

[Qemu-devel] [PATCH v2 1/6] Define MIPS_ABI_FP_UNKNOWN macro

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Add MIPS_ABI_FP_UNKNOWN as QEMU internal value to represent
unknown fp_abi (based on kernel mips/include/asm/elf.h definition)

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 include/elf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/elf.h b/include/elf.h
index 5f45f9b..c151164 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -87,6 +87,8 @@ typedef int64_t  Elf64_Sxword;
 #define EF_MIPS_MACH_LS3A     0x00a20000  /* ST Microelectronics Loongson 3A */
 #define EF_MIPS_MACH          0x00ff0000  /* EF_MIPS_MACH_xxx selection mask */
 
+#define MIPS_ABI_FP_UNKNOWN   (-1)        /* Unknown FP ABI (internal)       */
+
 #define MIPS_ABI_FP_ANY       0x0         /* FP ABI doesn't matter           */
 #define MIPS_ABI_FP_DOUBLE    0x1         /* -mdouble-float                  */
 #define MIPS_ABI_FP_SINGLE    0x2         /* -msingle-float                  */
-- 
1.9.1

[Qemu-devel] [PATCH v2 2/6] Extend image_info struct with MIPS specific fp_abi and interp_fp_abi fields

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Add MIPS specific image_info struct fields fp_abi and interp_fp_abi
to store executable and interpreter fp_abi values (based on kernel
struct arch_elf_state in mips/include/asm/elf.h).

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 linux-user/qemu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 1beb6a2..a752c1c 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -61,6 +61,10 @@ struct image_info {
         abi_ulong       interpreter_loadmap_addr;
         abi_ulong       interpreter_pt_dynamic_addr;
         struct image_info *other_info;
+#ifdef TARGET_MIPS
+        int             fp_abi;
+        int             interp_fp_abi;
+#endif
 };
 
 #ifdef TARGET_I386
-- 
1.9.1

[Qemu-devel] [PATCH v2 3/6] Extract MIPS abiflags from ELF file

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Read MIPS.abiflags section from ELF file into Mips_elf_abiflags_v0 struct.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 linux-user/elfload.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 055f6a9..5881233 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1517,11 +1517,25 @@ static void bswap_sym(struct elf_sym *sym)
     bswaptls(&sym->st_size);
     bswap16s(&sym->st_shndx);
 }
+
+#ifdef TARGET_MIPS
+static void bswap_mips_abiflags(Mips_elf_abiflags_v0 *abiflags)
+{
+    bswap16s(&abiflags->version);
+    bswap32s(&abiflags->ases);
+    bswap32s(&abiflags->isa_ext);
+    bswap32s(&abiflags->flags1);
+    bswap32s(&abiflags->flags2);
+}
+#endif
 #else
 static inline void bswap_ehdr(struct elfhdr *ehdr) { }
 static inline void bswap_phdr(struct elf_phdr *phdr, int phnum) { }
 static inline void bswap_shdr(struct elf_shdr *shdr, int shnum) { }
 static inline void bswap_sym(struct elf_sym *sym) { }
+#ifdef TARGET_MIPS
+static inline void bswap_mips_abiflags(Mips_elf_abiflags_v0 *abiflags) { }
+#endif
 #endif
 
 #ifdef USE_ELF_CORE_DUMP
@@ -2364,6 +2378,25 @@ static void load_elf_image(const char *image_name, int image_fd,
                 goto exit_errmsg;
             }
             *pinterp_name = interp_name;
+#ifdef TARGET_MIPS
+        } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {
+            Mips_elf_abiflags_v0 abiflags;
+            if (eppnt->p_filesz < sizeof(Mips_elf_abiflags_v0)) {
+                errmsg = "Invalid PT_MIPS_ABIFLAGS entry";
+                goto exit_errmsg;
+            }
+            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {
+                memcpy(&abiflags, bprm_buf + eppnt->p_offset,
+                       sizeof(Mips_elf_abiflags_v0));
+            } else {
+                retval = pread(image_fd, &abiflags, sizeof(Mips_elf_abiflags_v0),
+                               eppnt->p_offset);
+                if (retval != sizeof(Mips_elf_abiflags_v0)) {
+                    goto exit_perror;
+                }
+            }
+            bswap_mips_abiflags(&abiflags);
+#endif
         }
     }
 
-- 
1.9.1

[Qemu-devel] [PATCH v2 4/6] Read and set FP ABI value from MIPS abiflags

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Set fp_abi and interp_fp_abi values to current fp_abi value read from
MIPS.abiflags.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 linux-user/elfload.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 5881233..5bccd2e 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -2396,6 +2396,7 @@ static void load_elf_image(const char *image_name, int image_fd,
                 }
             }
             bswap_mips_abiflags(&abiflags);
+            info->fp_abi = abiflags.fp_abi;
 #endif
         }
     }
@@ -2708,6 +2709,9 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
             target_mmap(0, qemu_host_page_size, PROT_READ | PROT_EXEC,
                         MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
         }
+#ifdef TARGET_MIPS
+        info->interp_fp_abi = interp_info.fp_abi;
+#endif
     }
 
     bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc, &elf_ex,
-- 
1.9.1

[Qemu-devel] [PATCH v2 5/6] Determine the desired FPU mode

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Floating-point mode is calculated from MIPS.abiflags FP ABI value
(based on kernel implementation). Illegal combinations are rejected.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 linux-user/mips/cpu_loop.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/linux-user/mips/cpu_loop.c b/linux-user/mips/cpu_loop.c
index c9c20cf..97e4957 100644
--- a/linux-user/mips/cpu_loop.c
+++ b/linux-user/mips/cpu_loop.c
@@ -740,6 +740,34 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
     struct image_info *info = ts->info;
     int i;
 
+    struct mode_req {
+        bool single;
+        bool soft;
+        bool fr1;
+        bool frdefault;
+        bool fre;
+    };
+
+    static const struct mode_req fpu_reqs[] = {
+        [MIPS_ABI_FP_ANY]    = { true,  true,  true,  true,  true  },
+        [MIPS_ABI_FP_DOUBLE] = { false, false, false, true,  true  },
+        [MIPS_ABI_FP_SINGLE] = { true,  false, false, false, false },
+        [MIPS_ABI_FP_SOFT]   = { false, true,  false, false, false },
+        [MIPS_ABI_FP_OLD_64] = { false, false, false, false, false },
+        [MIPS_ABI_FP_XX]     = { false, false, true,  true,  true  },
+        [MIPS_ABI_FP_64]     = { false, false, true,  false, false },
+        [MIPS_ABI_FP_64A]    = { false, false, true,  false, true  }
+    };
+
+    /*
+     * Mode requirements when .MIPS.abiflags is not present in the ELF.
+     * Not present means that everything is acceptable except FR1.
+     */
+    static struct mode_req none_req = { true, true, false, true, true };
+
+    struct mode_req prog_req;
+    struct mode_req interp_req;
+
     for(i = 0; i < 32; i++) {
         env->active_tc.gpr[i] = regs->regs[i];
     }
@@ -747,6 +775,53 @@ void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
     if (regs->cp0_epc & 1) {
         env->hflags |= MIPS_HFLAG_M16;
     }
+
+#ifdef TARGET_ABI_MIPSO32
+# define MAX_FP_ABI MIPS_ABI_FP_64A
+#else
+# define MAX_FP_ABI MIPS_ABI_FP_SOFT
+#endif
+     if ((info->fp_abi > MAX_FP_ABI && info->fp_abi != MIPS_ABI_FP_UNKNOWN)
+        || (info->interp_fp_abi > MAX_FP_ABI &&
+            info->interp_fp_abi != MIPS_ABI_FP_UNKNOWN)) {
+        fprintf(stderr, "qemu: Unexpected FPU mode\n");
+        exit(1);
+    }
+
+    prog_req = (info->fp_abi == MIPS_ABI_FP_UNKNOWN) ? none_req
+                                            : fpu_reqs[info->fp_abi];
+    interp_req = (info->interp_fp_abi == MIPS_ABI_FP_UNKNOWN) ? none_req
+                                            : fpu_reqs[info->interp_fp_abi];
+
+    prog_req.single &= interp_req.single;
+    prog_req.soft &= interp_req.soft;
+    prog_req.fr1 &= interp_req.fr1;
+    prog_req.frdefault &= interp_req.frdefault;
+    prog_req.fre &= interp_req.fre;
+
+    bool cpu_has_mips_r2_r6 = env->insn_flags & ISA_MIPS32R2 ||
+                              env->insn_flags & ISA_MIPS64R2 ||
+                              env->insn_flags & ISA_MIPS32R6 ||
+                              env->insn_flags & ISA_MIPS64R6;
+
+    if (prog_req.fre && !prog_req.frdefault && !prog_req.fr1) {
+        env->CP0_Config5 |= (1 << CP0C5_FRE);
+        if (env->active_fpu.fcr0 & (1 << FCR0_FREP)) {
+            env->hflags |= MIPS_HFLAG_FRE;
+        }
+    } else if ((prog_req.fr1 && prog_req.frdefault) ||
+         (prog_req.single && !prog_req.frdefault)) {
+        if ((env->active_fpu.fcr0 & (1 << FCR0_F64)
+            && cpu_has_mips_r2_r6) || prog_req.fr1) {
+            env->CP0_Status |= (1 << CP0St_FR);
+            env->hflags |= MIPS_HFLAG_F64;
+        }
+    } else  if (!prog_req.fre && !prog_req.frdefault &&
+          !prog_req.fr1 && !prog_req.single && !prog_req.soft) {
+        fprintf(stderr, "qemu: Can't find a matching FPU mode\n");
+        exit(1);
+    }
+
     if (env->insn_flags & ISA_NANOMIPS32) {
         return;
     }
-- 
1.9.1

[Qemu-devel] [PATCH v2 6/6] Add prctl() PR_SET_FP_MODE and PR_GET_FP_MODE implementations

[Stefan Markovic]

From: Stefan Markovic <smarkovic@wavecomp.com>

Implement MIPS specific prctl() PR_SET_FP_MODE and PR_GET_FP_MODE emulation.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>
---
 linux-user/mips/target_syscall.h   |  2 ++
 linux-user/mips64/target_syscall.h |  2 ++
 linux-user/syscall.c               | 62 +++++++++++++++++++++++++++++++++++---
 3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/linux-user/mips/target_syscall.h b/linux-user/mips/target_syscall.h
index 33177af..d5509a3 100644
--- a/linux-user/mips/target_syscall.h
+++ b/linux-user/mips/target_syscall.h
@@ -247,5 +247,7 @@ static inline abi_ulong target_shmlba(CPUMIPSState *env)
 /* MIPS-specific prctl() options */
 #define TARGET_PR_SET_FP_MODE  45
 #define TARGET_PR_GET_FP_MODE  46
+#define TARGET_PR_FP_MODE_FR   (1 << 0)
+#define TARGET_PR_FP_MODE_FRE  (1 << 1)
 
 #endif /* MIPS_TARGET_SYSCALL_H */
diff --git a/linux-user/mips64/target_syscall.h b/linux-user/mips64/target_syscall.h
index c1160e6..8ccc468 100644
--- a/linux-user/mips64/target_syscall.h
+++ b/linux-user/mips64/target_syscall.h
@@ -244,5 +244,7 @@ static inline abi_ulong target_shmlba(CPUMIPSState *env)
 /* MIPS-specific prctl() options */
 #define TARGET_PR_SET_FP_MODE  45
 #define TARGET_PR_GET_FP_MODE  46
+#define TARGET_PR_FP_MODE_FR   (1 << 0)
+#define TARGET_PR_FP_MODE_FRE  (1 << 1)
 
 #endif /* MIPS64_TARGET_SYSCALL_H */
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 15b03e1..810a58b 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -9529,11 +9529,65 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_MIPS
         case TARGET_PR_GET_FP_MODE:
-            /* TODO: Implement TARGET_PR_SET_FP_MODE handling.*/
-            return -TARGET_EINVAL;
+        {
+            CPUMIPSState *env = ((CPUMIPSState *)cpu_env);
+            ret = 0;
+            if (env->CP0_Status & (1 << CP0St_FR)) {
+                ret |= TARGET_PR_FP_MODE_FR;
+            }
+            if (env->CP0_Config5 & (1 << CP0C5_FRE)) {
+                ret |= TARGET_PR_FP_MODE_FRE;
+            }
+            return ret;
+        }
         case TARGET_PR_SET_FP_MODE:
-            /* TODO: Implement TARGET_PR_GET_FP_MODE handling.*/
-            return -TARGET_EINVAL;
+        {
+            CPUMIPSState *env = ((CPUMIPSState *)cpu_env);
+            bool old_fr = env->CP0_Status & (1 << CP0St_FR);
+            bool new_fr = arg2 & TARGET_PR_FP_MODE_FR;
+            bool new_fre = arg2 & TARGET_PR_FP_MODE_FRE;
+
+            if (new_fr && !(env->active_fpu.fcr0 & (1 << FCR0_F64))) {
+                /* FR1 is not supported */
+                return -TARGET_EOPNOTSUPP;
+            }
+            if (!new_fr && (env->active_fpu.fcr0 & (1 << FCR0_F64))
+                && !(env->CP0_Status_rw_bitmask & (1 << CP0St_FR))) {
+                /* cannot set FR=0 */
+                return -TARGET_EOPNOTSUPP;
+            }
+            if (new_fre && !(env->active_fpu.fcr0 & (1 << FCR0_FREP))) {
+                /* Cannot set FRE=1 */
+                return -TARGET_EOPNOTSUPP;
+            }
+
+            int i;
+            fpr_t *fpr = env->active_fpu.fpr;
+            for (i = 0; i < 32 ; i += 2) {
+                if (!old_fr && new_fr) {
+                    fpr[i].w[!FP_ENDIAN_IDX] = fpr[i + 1].w[FP_ENDIAN_IDX];
+                } else if (old_fr && !new_fr) {
+                    fpr[i + 1].w[FP_ENDIAN_IDX] = fpr[i].w[!FP_ENDIAN_IDX];
+                }
+            }
+
+            if (new_fr) {
+                env->CP0_Status |= (1 << CP0St_FR);
+                env->hflags |= MIPS_HFLAG_F64;
+            } else {
+                env->CP0_Status &= ~(1 << CP0St_FR);
+            }
+            if (new_fre) {
+                env->CP0_Config5 |= (1 << CP0C5_FRE);
+                if (env->active_fpu.fcr0 & (1 << FCR0_FREP)) {
+                    env->hflags |= MIPS_HFLAG_FRE;
+                }
+            } else {
+                env->CP0_Config5 &= ~(1 << CP0C5_FRE);
+            }
+
+            return 0;
+        }
 #endif /* MIPS */
 #ifdef TARGET_AARCH64
         case TARGET_PR_SVE_SET_VL:
-- 
1.9.1

Re: [Qemu-devel] [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE

[Aleksandar Markovic]

> From: Stefan Markovic <stefan.markovic@rt-rk.com>
> Subject: [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE
> 
> From: Stefan Markovic <smarkovic@wavecomp.com>
> 
> This series includes support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE. This requires
> extracting MIPS.abiflags section from ELF file and fp_abi value handling.

Stefan, the patch titles don't have appropriate prefixes "elf:" and "user-mode:", but I can fix that while integrating.

Laurent, heads up: I plan to include this series in a MIPS pull request that is planned for today.

Thanks,
Aleksandar

Re: [Qemu-devel] [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE

[Laurent Vivier]

Le 29/10/2018 à 15:53, Aleksandar Markovic a écrit :
>> From: Stefan Markovic <stefan.markovic@rt-rk.com>
>> Subject: [PATCH v2 0/6] target/mips: Add support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE
>>
>> From: Stefan Markovic <smarkovic@wavecomp.com>
>>
>> This series includes support for prctl() PR_GET_FP_MODE and PR_SET_FP_MODE. This requires
>> extracting MIPS.abiflags section from ELF file and fp_abi value handling.
> 
> Stefan, the patch titles don't have appropriate prefixes "elf:" and "user-mode:", but I can fix that while integrating.
> 
> Laurent, heads up: I plan to include this series in a MIPS pull request that is planned for today.

No problem. I didn't have the time to do anything today.

Thanks,
Laurent