x86: limit number of hypercall parameters to 5

Today there is no hypercall with more than 5 parameters, while the ABI
allows up to 6 parameters. Especially for the X86 32-bit case using
6 parameters would require to run without frame pointer, which isn't
very fortunate. Note that for Arm the limit is 5 parameters already.

So limit the maximum number of parameters to 5 for x86, too.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/hvm/hypercall.c b/xen/arch/x86/hvm/hypercall.c
index 63bed52e402d49b184568e7ea9f869399b715007..1f04ffb272499eedd3c0341b418e9f07b1a25308 100644 (file)
--- a/xen/arch/x86/hvm/hypercall.c
+++ b/xen/arch/x86/hvm/hypercall.c
@@ -239,10 +239,9 @@ int hvm_hypercall(struct cpu_user_regs *regs)
         unsigned long rdx = regs->rdx;
         unsigned long r10 = regs->r10;
         unsigned long r8 = regs->r8;
-        unsigned long r9 = regs->r9;
 
-        HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%lu(%lx, %lx, %lx, %lx, %lx, %lx)",
-                    eax, rdi, rsi, rdx, r10, r8, r9);
+        HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%lu(%lx, %lx, %lx, %lx, %lx)",
+                    eax, rdi, rsi, rdx, r10, r8);
 
 #ifndef NDEBUG
         /* Deliberately corrupt parameter regs not used by this hypercall. */
@@ -252,13 +251,11 @@ int hvm_hypercall(struct cpu_user_regs *regs)
         case 1: rsi = 0xdeadbeefdeadf00dUL; fallthrough;
         case 2: rdx = 0xdeadbeefdeadf00dUL; fallthrough;
         case 3: r10 = 0xdeadbeefdeadf00dUL; fallthrough;
-        case 4: r8 = 0xdeadbeefdeadf00dUL; fallthrough;
-        case 5: r9 = 0xdeadbeefdeadf00dUL;
+        case 4: r8 = 0xdeadbeefdeadf00dUL;
         }
 #endif
 
-        regs->rax = hvm_hypercall_table[eax].native(rdi, rsi, rdx, r10, r8,
-                                                    r9);
+        regs->rax = hvm_hypercall_table[eax].native(rdi, rsi, rdx, r10, r8);
 
 #ifndef NDEBUG
         if ( !curr->hcall_preempted )
@@ -266,7 +263,6 @@ int hvm_hypercall(struct cpu_user_regs *regs)
             /* Deliberately corrupt parameter regs used by this hypercall. */
             switch ( hypercall_args_table[eax].native )
             {
-            case 6: regs->r9  = 0xdeadbeefdeadf00dUL; fallthrough;
             case 5: regs->r8  = 0xdeadbeefdeadf00dUL; fallthrough;
             case 4: regs->r10 = 0xdeadbeefdeadf00dUL; fallthrough;
             case 3: regs->rdx = 0xdeadbeefdeadf00dUL; fallthrough;
@@ -283,10 +279,9 @@ int hvm_hypercall(struct cpu_user_regs *regs)
         unsigned int edx = regs->edx;
         unsigned int esi = regs->esi;
         unsigned int edi = regs->edi;
-        unsigned int ebp = regs->ebp;
 
-        HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%lu(%x, %x, %x, %x, %x, %x)", eax,
-                    ebx, ecx, edx, esi, edi, ebp);
+        HVM_DBG_LOG(DBG_LEVEL_HCALL, "hcall%lu(%x, %x, %x, %x, %x)", eax,
+                    ebx, ecx, edx, esi, edi);
 
 #ifndef NDEBUG
         /* Deliberately corrupt parameter regs not used by this hypercall. */
@@ -296,14 +291,12 @@ int hvm_hypercall(struct cpu_user_regs *regs)
         case 1: ecx = 0xdeadf00d; fallthrough;
         case 2: edx = 0xdeadf00d; fallthrough;
         case 3: esi = 0xdeadf00d; fallthrough;
-        case 4: edi = 0xdeadf00d; fallthrough;
-        case 5: ebp = 0xdeadf00d;
+        case 4: edi = 0xdeadf00d;
         }
 #endif
 
         curr->hcall_compat = true;
-        regs->rax = hvm_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi,
-                                                    ebp);
+        regs->rax = hvm_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi);
         curr->hcall_compat = false;
 
 #ifndef NDEBUG
@@ -312,7 +305,6 @@ int hvm_hypercall(struct cpu_user_regs *regs)
             /* Deliberately corrupt parameter regs used by this hypercall. */
             switch ( hypercall_args_table[eax].compat )
             {
-            case 6: regs->rbp = 0xdeadf00d; fallthrough;
             case 5: regs->rdi = 0xdeadf00d; fallthrough;
             case 4: regs->rsi = 0xdeadf00d; fallthrough;
             case 3: regs->rdx = 0xdeadf00d; fallthrough;
@@ -349,7 +341,7 @@ enum mc_disposition hvm_do_multicall_call(struct mc_state *state)
             func = array_access_nospec(hvm_hypercall_table, call->op).native;
         if ( func )
             call->result = func(call->args[0], call->args[1], call->args[2],
-                                call->args[3], call->args[4], call->args[5]);
+                                call->args[3], call->args[4]);
         else
             call->result = -ENOSYS;
     }
@@ -361,7 +353,7 @@ enum mc_disposition hvm_do_multicall_call(struct mc_state *state)
             func = array_access_nospec(hvm_hypercall_table, call->op).compat;
         if ( func )
             call->result = func(call->args[0], call->args[1], call->args[2],
-                                call->args[3], call->args[4], call->args[5]);
+                                call->args[3], call->args[4]);
         else
             call->result = -ENOSYS;
     }

diff --git a/xen/arch/x86/pv/hypercall.c b/xen/arch/x86/pv/hypercall.c
index 3579ba905c1c3ebf84654e66f5a04d911035efd5..16a77e3a359e2dafe2a431f7326eb6a37ca415f8 100644 (file)
--- a/xen/arch/x86/pv/hypercall.c
+++ b/xen/arch/x86/pv/hypercall.c
@@ -145,7 +145,6 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
         unsigned long rdx = regs->rdx;
         unsigned long r10 = regs->r10;
         unsigned long r8 = regs->r8;
-        unsigned long r9 = regs->r9;
 
 #ifndef NDEBUG
         /* Deliberately corrupt parameter regs not used by this hypercall. */
@@ -155,18 +154,17 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
         case 1: rsi = 0xdeadbeefdeadf00dUL; fallthrough;
         case 2: rdx = 0xdeadbeefdeadf00dUL; fallthrough;
         case 3: r10 = 0xdeadbeefdeadf00dUL; fallthrough;
-        case 4: r8 = 0xdeadbeefdeadf00dUL; fallthrough;
-        case 5: r9 = 0xdeadbeefdeadf00dUL;
+        case 4: r8 = 0xdeadbeefdeadf00dUL;
         }
 #endif
         if ( unlikely(tb_init_done) )
         {
-            unsigned long args[6] = { rdi, rsi, rdx, r10, r8, r9 };
+            unsigned long args[5] = { rdi, rsi, rdx, r10, r8 };
 
             __trace_hypercall(TRC_PV_HYPERCALL_V2, eax, args);
         }
 
-        regs->rax = pv_hypercall_table[eax].native(rdi, rsi, rdx, r10, r8, r9);
+        regs->rax = pv_hypercall_table[eax].native(rdi, rsi, rdx, r10, r8);
 
 #ifndef NDEBUG
         if ( !curr->hcall_preempted )
@@ -174,7 +172,6 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
             /* Deliberately corrupt parameter regs used by this hypercall. */
             switch ( hypercall_args_table[eax].native )
             {
-            case 6: regs->r9  = 0xdeadbeefdeadf00dUL; fallthrough;
             case 5: regs->r8  = 0xdeadbeefdeadf00dUL; fallthrough;
             case 4: regs->r10 = 0xdeadbeefdeadf00dUL; fallthrough;
             case 3: regs->rdx = 0xdeadbeefdeadf00dUL; fallthrough;
@@ -192,7 +189,6 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
         unsigned int edx = regs->edx;
         unsigned int esi = regs->esi;
         unsigned int edi = regs->edi;
-        unsigned int ebp = regs->ebp;
 
 #ifndef NDEBUG
         /* Deliberately corrupt parameter regs not used by this hypercall. */
@@ -202,20 +198,19 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
         case 1: ecx = 0xdeadf00d; fallthrough;
         case 2: edx = 0xdeadf00d; fallthrough;
         case 3: esi = 0xdeadf00d; fallthrough;
-        case 4: edi = 0xdeadf00d; fallthrough;
-        case 5: ebp = 0xdeadf00d;
+        case 4: edi = 0xdeadf00d;
         }
 #endif
 
         if ( unlikely(tb_init_done) )
         {
-            unsigned long args[6] = { ebx, ecx, edx, esi, edi, ebp };
+            unsigned long args[5] = { ebx, ecx, edx, esi, edi };
 
             __trace_hypercall(TRC_PV_HYPERCALL_V2, eax, args);
         }
 
         curr->hcall_compat = true;
-        regs->eax = pv_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi, ebp);
+        regs->eax = pv_hypercall_table[eax].compat(ebx, ecx, edx, esi, edi);
         curr->hcall_compat = false;
 
 #ifndef NDEBUG
@@ -224,7 +219,6 @@ _pv_hypercall(struct cpu_user_regs *regs, bool compat)
             /* Deliberately corrupt parameter regs used by this hypercall. */
             switch ( hypercall_args_table[eax].compat )
             {
-            case 6: regs->ebp = 0xdeadf00d; fallthrough;
             case 5: regs->edi = 0xdeadf00d; fallthrough;
             case 4: regs->esi = 0xdeadf00d; fallthrough;
             case 3: regs->edx = 0xdeadf00d; fallthrough;
@@ -262,7 +256,7 @@ enum mc_disposition pv_do_multicall_call(struct mc_state *state)
              pv_hypercall_table[op].compat )
             call->result = pv_hypercall_table[op].compat(
                 call->args[0], call->args[1], call->args[2],
-                call->args[3], call->args[4], call->args[5]);
+                call->args[3], call->args[4]);
         else
             call->result = -ENOSYS;
     }
@@ -276,7 +270,7 @@ enum mc_disposition pv_do_multicall_call(struct mc_state *state)
              pv_hypercall_table[op].native )
             call->result = pv_hypercall_table[op].native(
                 call->args[0], call->args[1], call->args[2],
-                call->args[3], call->args[4], call->args[5]);
+                call->args[3], call->args[4]);
         else
             call->result = -ENOSYS;
     }

diff --git a/xen/common/trace.c b/xen/common/trace.c
index a2a389a1c7c3b1dc082120397af821ee2b36169a..61fecc2b2bd29d95fff68d92882d006aacbe5ead 100644 (file)
--- a/xen/common/trace.c
+++ b/xen/common/trace.c
@@ -822,7 +822,7 @@ void __trace_hypercall(uint32_t event, unsigned long op,
 {
     struct {
         uint32_t op;
-        uint32_t args[6];
+        uint32_t args[5];
     } d;
     uint32_t *a = d.args;
 

diff --git a/xen/include/asm-x86/hypercall.h b/xen/include/asm-x86/hypercall.h
index 0ae3b8b043b24f0f4238698602eb4d6c814e41c3..5d394d492318e26d34a844b03307df5808ab5de7 100644 (file)
--- a/xen/include/asm-x86/hypercall.h
+++ b/xen/include/asm-x86/hypercall.h
@@ -13,7 +13,7 @@
 
 typedef unsigned long hypercall_fn_t(
     unsigned long, unsigned long, unsigned long,
-    unsigned long, unsigned long, unsigned long);
+    unsigned long, unsigned long);
 
 typedef struct {
     hypercall_fn_t *native;